Biomedical subjects

Y Aoki

Publications and source records attributed to Y Aoki.

At least 307 records · Page 17Linked to original sources

PubMed1997

Further clonal expansion of T cells upon rechallenge of superantigen staphylococcal enterotoxin A.

Superantigens are known to induce clonal anergy and/or deletion in reactive T cells peripherally. This study was undertaken to investigate the T-cell status early after exposure to staphylococcal enterotoxin A (SEA) in vivo and in vitro. At the peak of clonal expansion following the administration of 5 microg SEA (i.e., 2 days after the injection), C57BL/6 mice were rechallenged with the same dose of SEA in vivo. The secondary stimulation augmented clonal expansion of the T cells bearing Vbeta3 and Vbeta11 in both CD4+ and CD8+ populations. In vitro restimulation of the spleen cells taken from the SEA-primed mice also induced further expansion of the Vbeta3+ T cells during 2 days of culturing, whereas without restimulation, a marked reduction of Vbeta3+ T cells occurred. The spleen cells from the SEA-primed mice were hyper-reactive to in vitro restimulation with SEA as measured by 3H-TdR uptake on day 1 of culturing, but augmented proliferation leveled off thereafter. By day 3, the values of 3H-TdR uptake were less than 20% of those of the controls in which spleen cells from native mice were stimulated with SEA in vitro. These results suggest that T cells exposed to SEA in vivo are still capable of proliferating upon SEA rechallenge, but subsequently, the proliferation starts to wane.

Animals↗

PubMed1997

Nerve-sparing retroperitoneal lymph node dissection for metastatic testicular cancer.

BACKGROUND: Nerve-sparing techniques are used during retroperitoneal lymph node dissection (RPLND) in patients with early stage testicular cancer to preserve postoperative ejaculatory function. Indications for the procedures have been extended to patients with a postchemotherapy retroperitoneal residual mass without compromising the efficacy of surgery. We report 6 cases diagnosed with metastatic testicular cancer who underwent nerve-sparing RPLND. METHODS: Between January 1994 and March 1996, 6 patients with metastatic testicular cancer underwent nerve-sparing RPLND. Five of these patients received primary chemotherapy and a retroperitoneal residual mass. Four patients underwent complete bilateral RPLND and 2 underwent unilateral template surgery. RESULTS: After a mean follow-up of 18.7 months (range, 8 to 34), there have been no local recurrences and 5 (83%) patients report antegrade ejaculation. CONCLUSION: Nerve-sparing RPLND is applicable for selected patients with metastatic testicular cancer without increasing the risk of local recurrence. Ejaculatory function is preserved in the majority of patients, contributing to the improvement of the quality of life in men who require such surgery.

Adolescent↗

PubMed1997

Value of systematic transition zone biopsy in the detection of prostate cancer.

BACKGROUND: We evaluated routine transition zone biopsies for the detection of prostate cancer. METHODS: Systematic sextant transrectal biopsies, including 2 systematic transition zone biopsies (sextant biopsy group), were performed on 196 consecutive patients. Biopsies were based on indications from digital rectal examination and/or a serum PSA level greater than 4.0 ng/mL. During the same period, 21 patients with persistently elevated PSA levels and earlier negative systematic biopsies also had the sextant biopsy (re-biopsy group). The sextant biopsy group was compared with 124 cases in our previous cancer detection program who had systematic quadrant biopsies targeted to the peripheral zone (quadrant biopsy group). RESULTS: Between the sextant and quadrant biopsy groups, the difference in rate of cancer detection was not significant statistically. Of the sextant biopsy group, 64 (33%) demonstrated malignancy, including 9 (4.6%) with cancer found exclusively in the peripheral zone and 55 (28%) both in the peripheral and transition zones. No cancer was found exclusively in the transition zone. Of the re-biopsy group, all 4 cancers (19%) were detected in the transition zone, 2 of them exclusively in the transition zone. CONCLUSION: Routine transition zone biopsies did not increase the detection rate of prostate cancer. Systematic transition zone biopsies proved useful to the patients with persistently elevated PSA values and negative results in previous systematic peripheral zone biopsies.

Aged↗

PubMed1997

Immunohistochemical study of cathepsin G and medullasin in inflamed gingival tissues from periodontal patients.

Cathepsin G and medullasin are 2 major serine proteinases associated with the granular fraction of polymorphonuclear leukocytes (PMNs). To know their possible involvement in the pathophysiological gingival connective tissue turnover, we have determined the distribution and localization of these 2 enzymes in inflamed gingival tissues from periodontal patients by immunohistochemistry with discriminating antibodies specific for each enzyme. The gingival connective tissues were obtained from periodontitis patients with various inflammatory conditions and control healthy subjects without any clinical signs of periodontal inflammation. In all gingival specimens examined, cathepsin G and medullasin were found mainly in neutrophil-like cells and partly in macrophage-like cells. No positive staining for both enzymes was obtained in endothelial cells and fibroblasts in every part of the gingival tissues. Immunoreactivity for each enzyme in the gingival tissues from the periodontitis group was stronger and greater in the intensity and frequency than that from the control group and appeared to be increased with the severity of the disease In both groups, the number of immunoreactive cells for each enzyme was greater in the vicinity of pocket epithelium (zone I) than in the area of central connective tissue (zone II) or the area subjacent to the oral epithelium (zone III). While both enzymes in zones II and III were exclusively found in coarse granules, their stainings in zone I were not only coarse but also diffuse. These results strongly suggest that both enzymes may have some association with inflamed gingival tissue degradation.

Adult↗

PubMed1997

[Analysis of 58 cases of tuberculosis experienced in the recent 8 years at Tsukuba University Hospital].

In the past 8 years, we have experienced 58 cases of tuberculosis at Tsukuba University Hospital. Retrospective analysis of these patients was made to clarify the circumstances of tuberculosis in hospitals where no special isolated ward for tuberculosis patients is prepared. The half were above 60 years old and a fourth were under 40 years old. Approximately two thirds of the patients had underlying diseases and malignancy was the most common. Most of the patients complained of cough, sputum, and/or fever. Thirty-one patients were diagnosed as pulmonary tuberculosis, 18 were extra-pulmonary, and 9 were complicated with both. Extra-pulmonary cases or patients who had underlying diseases showed unusual symptoms, and early diagnosis was difficult in several cases. Mycobacterium tuberculosis was detected in over 80% of the patients, and polymerase chain reaction procedure seemed to be useful for definite and rapid diagnosis of tuberculosis. There are no special isolated wards for tuberculosis patients in our hospital, but some patients could not be transferred because of their severe condition or complicated diseases. To prevent nosocomial infections of tuberculosis including occupational infection in the medical staff, early diagnosis, management of high risk staff, isolation rooms for patients who have potential risk of causative sauce of infection are needed.

Adult↗

PubMed1997

Clonal expansion of superantigen-reactive T cells is resistant to FK506 in mice with AIDS.

Subcutaneous injection of FK506 (10 mg/kg of body weight) completely blocked the clonal expansion of staphylococcal enterotoxin A (SEA)-reactive T cells in healthy (control) mice after SEA injection but did not disturb it in mice with murine AIDS (MAIDS) caused by infection with LP-BM5 murine leukemia virus. MAIDS mice are characterized by utilization of a FK506-insensitive pathway for clonal expansion of superantigen-reactive T cells.

Animals↗

PubMed1997

Human airway epithelial cells express interleukin-2 in vitro.

Human airway epithelial cells (AEC) produce the T cell growth factor interleukin (IL)-2 that likely modulates the T cell lung inflammatory response. IL-2 mRNA from cultured AEC and from Jurkat T cells was analyzed by reverse transcription-polymerase chain reaction and Northern hybridization. IL-2 mRNA is present constitutively in AEC and is enhanced twofold after stimulation with phorbol 12-myristate 13-acetate (PMA; 20 ng/ml) + histamine (2 mM). Normal human AEC secrete IL-2 at rest (7 pg/ml), and IL-2 secretion is increased threefold after stimulation with PMA + histamine; this increase is inhibited by dexamethasone and diphenhydramine. Transcriptional regulation of IL-2 was investigated with a transgenic human AEC line, 16HBE/IL-2 luciferase; there is constitutive IL-2 transcription at rest, and IL-2 transcription is enhanced 8-fold by PMA and 25-fold by PMA + histamine. IL-2 regulation differs fundamentally between AEC and Jurkat T cells. AEC IL-2 likely promotes local proliferation of T cells and may contribute to pathological airway inflammation in asthma.

Adult↗

PubMed1997

Characterization of mutant holocarboxylase synthetase (HCS): a Km for biotin was not elevated in a patient with HCS deficiency.

Holocarboxylase synthetase (HCS) is an essential enzyme for the biotinylation of several mammalian carboxylases. A deficiency of HCS is accountable for early onset biotin-responsive multiple carboxylase deficiency. To address the mechanism of biotin responsiveness, we analyzed the kinetic properties of the previously identified mutant, L237P, and another mutant, V550M, described in this report. The V550M mutant contains a G to A transition at position 1935, which is within the putative biotin binding site, whereas the mutation in L237P occurs outside the biotin binding site. Km and Vmax values for the mutant proteins were determined by overexpressing cDNAs encoding the mutants in transformed fibroblasts from an HCS-deficient patient. Enzyme activity assays were performed using apo-carboxyl carrier protein as a substrate. A Km for biotin that was larger than the value found for the wild-type cDNA was observed in fibroblasts transfected with the V550M cDNA, but not the L237P cDNA. The Vmax for the expressed L237P cDNA was 4.3% of that observed for the wild-type cDNA. Biotin-responsiveness in the patient with the L237P mutation was neither due to an increased affinity for biotin nor a restoration of stability of the mutant by biotin treatment. A new mechanism of biotin responsiveness in HCS deficiency is presented.

Biotin↗

PubMed1997

Regulation of the rat proopiomelanocortin gene expression in AtT-20 cells. II: Effects of the pituitary adenylate cyclase-activating polypeptide and vasoactive intestinal polypeptide.

Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP), members of the glucagon-secretin family, have recently been suggested to be involved in the regulation of corticotropin (ACTH) secretion. In this study, we examined the effects of both peptides on POMC gene expression. Using AtT20PL, a clone of the AtT20 mouse corticotroph tumor cells stably transfected with 0.7 kb of the rat POMC 5' promoter-luciferase fusion gene, the effects of both peptides on the POMC promoter activity were estimated by a luciferase assay. PACAP stimulated POMC 5' promoter activity as well as cAMP generation and ACTH secretion in a dose- and time-dependent manner, with the maximal effect being observed 3 h after the start of incubation. A similar effect was observed with VIP. Although the combined effects of PACAP/CRH or VIP/CRH were greater than that of either hormone alone, no such effect was observed between PACAP and VIP. Furthermore, RT-PCR analysis showed the presence of only the PVR3 receptor subtype in this cell line, which is known to have a similar affinity to PACAP and VIP, indicating that both peptides exert their effects through the same receptor. In contrast to the effect of CRH, which was completely abolished by a protein kinase A inhibitor H89, the effects of PACAP/VIP on POMC expression persisted during H89 treatment, suggesting the involvement of alternative intracellular signaling pathway(s) distinct from the protein kinase A system. Our results suggest that PACAP and VIP have positive effects on POMC gene expression and that multiple signaling pathways are involved in the transcriptional event.

Adenylyl Cyclases↗

PubMed1997

Regulation of the rat proopiomelanocortin gene expression in AtT-20 cells. I: Effects of the common secretagogues.

Although the effects of the various secretagogues on corticotropin (ACTH) secretion have been well studied, their effects on the POMC gene expression have not been thoroughly characterized. In this study, we established a new model system using the AtT20 mouse corticotroph tumor cell line transfected stably with a plasmid containing 0.7 kb of the rat POMC 5' promoter-luciferase fusion gene. The responsiveness to exogenous CRH improved markedly when the cells were cultured with low serum medium (1% FBS) compared with serum rich medium (10%). Using this culture condition, we examined the effects of not only CRH but also other secretagogues such as catecholamines, vasopressin, and angiotensin II, upon the transcriptional activity of the POMC gene. CRH stimulated POMC promoter activity (3.5-fold increase) as well as cAMP generation and ACTH secretion in a dose- and time-dependent manner, with the maximal effect being observed 3-5 h after the start of incubation. Catecholamines, especially epinephrine (10 nM and above), also stimulated all parameters, although less potently than CRH, and the effect was mimicked by the beta-, but not alpha-adrenergic, agonist, suggesting the involvement of the beta-adrenergic receptor. The combined effects of epinephrine and CRH were greater in all parameters than those of CRH alone, and the effects of both hormones were completely blocked by H89, an inhibitor of protein kinase A. Vasopressin and angiotensin II showed minimal effects on POMC expression. Our results suggest that 1) catecholamines, as well as CRH, positively regulate the POMC gene at physiological concentrations; 2) the cAMP-PKA system is the common intracellular signaling pathway for CRH and catecholamines; and 3) vasopressin and angiotensin II also have weak but significant stimulatory effects on POMC promoter activity.

Adrenergic beta-Agonists↗

PubMed1997

Plasma levels of diethylcarbamazine and their effects on implanted microfilariae of Brugia pahangi in rats.

Plasma level of diethylcarbamazine (DEC) was measured by using gas chromatography and was compared to the changes of microfilaremia after an intraperitoneal injection with 200 mg/kg of DEC in rats. The microfilaremia was induced artificially by an intravenous implantation with 2 x 10(5) Brugia pahangi microfilariae (mf) 1 day before DEC treatment. The rats treated with DEC showed a rapid and significant decrease in mf number in the circulation within 30 min, continued for 4 hr, and then increased rapidly. DEC seemed to cause transient but significant suppression of microfilaremia of B. pahangi in rats directly.

Animals↗

PubMed1997

Effect of piped water supply on human water contact patterns in a Schistosoma haematobium-endemic area in Coast Province, Kenya.

The effect of a piped water supply on human water contact in a Schistosoma haematobium-endemic area in Coast Province, Kenya was studied. After the construction of five community standpipes and one shower unit, there was a 35.1% reduction in the number of people observed using river water, a 44.1% reduction in the frequency of contact with river water, and a 25.4% reduction in the amount of contact. The frequency of river water contact per person also decreased significantly, but the amount of contact per person did not decrease. The total frequency of contact decreased significantly except for washing clothes by the river, washing utensils, and fishing. The frequency per person did not change for most of the activities and significantly increased for washing clothes. The frequency of river water contact in households with high piped water consumption showed a significant decrease compared with those with low piped water consumption. The volume of consumption of piped water was inversely proportional to the distance from the home to the community standpipe. These results indicate that in the study area, the effect of a piped water supply on river water contact behavior was heterologous while the total river water contact decreased significantly, and that the piped water had a beneficial effect on some villagers but very little effect on others.

Adolescent↗

PubMed1997

Cercarial density in the river of an endemic area of schistosomiasis haematobia in Kenya.

The cercarial density in natural water and number of infected Bulinus globosus were monitored over a one-year period to identify the transmission foci in an endemic area of schistosomiasis haematobia in Kenya. Overall prevalence and intensity of infection of the study community were 59.2% and 10.9 eggs/10 ml of urine. Cercariometry was carried out on 456 occasions at 20 study sites while snail sampling was done on 465 occasions at the same sites over a one-year period. Cercariometry was exclusively done at flowing water habitats. The results showed the focality and seasonality of transmission. Cercariae were detected on 44 occasions at 11 sites. The detections were made on seven occasions at two study sites, six occasions at one site, four occasions at four sites, three occasions at one site, two occasions at two sites, and one occasion at one site. Densities of 1-4 cercariae/100 liters of water were found on 31 occasions. Five to nine cercariae/100 liters of water were found on seven occasions, 10-19 cercariae/100 liters of water were found on two occasions, and high cercarial densities greater than 20 cercariae/100 liters of water were found on four occasions. The highest count was 52 cercariae/100 liters of water. The presence of cercariae in natural water was shown to depend on the water temperature, but the intensity and duration of sunlight did not affect the presence of cercariae in water. The monthly variability of cercarial density was proportional to the number of infected snails. Cercarial density was highest in March and April, in the middle of the rainy season, whereas no cercariae were detected in cool dry season. The snail population peaked late in March, the beginning of the long rainy season, remained high for two months, and decreased rapidly late in May when heavy rain occurred. The overall infection rate of snails was 7.3% and the majority of infected snails were collected from March to May. There was no definite correlation between the presence or absence of cercariae and infected snails. Cercariae were frequently found where infected snails were absent and cercariae were sometimes absent where infected snails were present. Cercariometry and snail sampling remain quite complementary in identifying the transmission foci of schistosomiasis.

Age Factors↗

PubMed1997

[Experimental and clinical studies for laser irradiation to the prostate].

BACKGROUND: The object of the study is to observe the influence of laser on the prostate tissue and to evaluate the efficiency as well as safety. METHODS: Ten canine prostates were irradiated by Nd:YAG laser with a lateral firing fiber. The lasing was carried out either spot or running irradiation on the free beam method. Laser energy was applied for 30, 40 and 60 seconds at 50 watts power output. On the basis of the animal experiments, clinical application was performed in patients with BPH. RESULTS: Immediately after the irradiation, the prostate became swollen by the edema. But the irradiated tissue became necrotic and sloughed resulting in a big cavity of the prostatic urethra by two weeks. The higher the energy density with spot irradiation, the larger the tissue effect as well as the risks. Therefore, it would be important to combine spot with running irradiation for optimal energy density. Clinically, subjective and objective improvements were noted significantly after treatment. CONCLUSION: Thus, the endoscopical laser prostatic therapy proved to be useful and safe from the present fundamental and clinical investigations.

Aged↗

PubMed1997

[Gamma knife radiosurgery for metastatic brain tumors: neuropathological report of two autopsy cases and review of literatures].

More than 40,000 cases have been treated with gamma knife radiosurgery, but few neuropathological reports are available. This paper describes two autopsy cases in which the patients had been treated with gamma knife. As these patients died 67 and 24 days after therapy, early neuropathological changes are reported. The first case was a 58-year-old woman diagnosed with multiple brain metastases from breast cancer. One of these lesions, in the medullaoblongata, was irradiated with a gamma knife. Sixty-seven days later, she died from heart failure. The second case was a 69-year-old man diagnosed with multiple brain metastases from lung cancer. One of these lesions, in the pons, was irradiated with a gamma knife. Twenty-four days later, he died from acute renal failure caused by hepatorenal syndrome. In both cases, the irradiated lesions were well demarcated from the undamaged surrounding tissues on light microscopy. Histologically, the tumor cells showed a variety of degenerative changes, such as pyknosis, multinuclear cells, and vacuolar degeneration in the cytoplasm. Fibrosis, more prominent in the first case, was observed spreading in the irradiation field, adhering to the hyalinized and thickened vessel walls. Demyelination was also observed in the first case. As far as we know, this report is the first published description of fibrosis in the radiosurgical irradiation field.

Aged↗

PubMed1997

ABO genotyping by PCR-direct sequencing.

The PCR-direct sequence method was applied to ABO genotyping. At the 261st nucleotide of the genes of A and B glycosyltrasferase, it was easily detected that the nucleotide was guanine in AA, AB and BB genotypes and that the nucleotide was ademine in only OO. In AO and BO, substitution of A to G was confirmed by the dye primer method, but it was difficult to detect correctly by the dye terminator method. At the 297th, nucleotide substitution between A and B alleles was confirmed by the both methods. As this position, O allele was subdivided into three types, OAOA, OGOG and OAOG. At the 703rd, nucleotide substitution between A and B alleles was easily detected by the both methods. The PCR-direct sequence method was suitable to confirm the nucleotide substitution or deletion directly and to prevent the mistyping by other methods.

ABO Blood-Group System↗

PubMed1997

[Application of stochastical analysis to maternity testing without putative mother].

In a maternity test in which the putative mother was deceased, the cumulative probability of maternity (PM) was calculated at 0.822 from 24 genetic markers by the stochastical method. This PM may not be evaluated in the same way as that of usual paternity cases. We applied the same method to two families whose blood relationships were undoubted. We compared the PMs in the cases in which maternal genotypes were estimated and were defined. Also, we calculated the PMs in the case of real maternal relationship and false maternal one. The estimated PM from real maternity relationship was significantly higher than that from false maternal one.

ABO Blood-Group System↗

PubMed1997

Laceration of the liver with delayed massive intra-abdominal hemorrhage: a case report of child abuse.

A 3-year-old girl was found unresponsive in the bedroom and expired at a hospital. Autopsy revealed massive intra-abdominal bleeding due to laceration of the liver and mesenterium with multiple rib fractures and multiple fresh and old bruises. The time of the assault causing the liver trauma was questioned because the perpetrator, her mother's boyfriend, denied any outrages on that particular day although he confessed that he had physically abused her for several months. Microscopically, numerous polymorph leucocytes infiltrated exclusively surrounding the lacerated area of the liver. Many hepatocytes were necrotic and cord arrangement of the parenchymal cells was destroyed. There should be a certain time lag between the major assault and massive intra-abdominal hemorrhage, which was not inconsistent with the statement of the perpetrator.

Abdominal Injuries↗