Biomedical subjects

Y Kurokawa

Publications and source records attributed to Y Kurokawa.

At least 19 recordsLinked to original sources

PubMed2005

[Lung volume reduction surgery for chronic pulmonary emphysema in elderly patients].

We have performed thoracoscopic lung volume reduction surgery (LVRS) for severe chronic pulmonary emphysema irrespective of the patient's age. Between May 1993 and April 2004, 9 patients older than 75 years underwent LVRS at our hospital. Three of the 9 patients substantially improved lung function and quality of life after LVRS. One patient slightly improved them but went back to the preoperative condition 5 years after LVRS. The other 5 patients showed no clinical improvement after LVRS, 3 of the 5 developed CO2 narcosis and failed weaning from the respirator. Although patient's age older than 75 years is not contra-indication for LVRS, careful selection is needed for LVRS in elderly patients.

Age Factors↗

PubMed2004

Intraepithelial CD8+ T-cell-count becomes a prognostic factor after a longer follow-up period in human colorectal carcinoma: possible association with suppression of micrometastasis.

T-cell infiltration into human cancer tissues can be a manifestation of host immune responses to cancer cells. The present study was undertaken to explore the clinicopathological significance of intraepithelial CD8(+) T cells using 371 consecutively sampled human colorectal carcinomas. By univariate analysis, we noted that the survival curves by intraepithelial CD8(+) T cells became separated only after 1 to 2 years postoperation. Multivariate analyses revealed that the beneficial effect of this factor becomes significant only after a longer (more than 2 year), but not after a shorter (less than 2 year) follow-up period. Furthermore, the number of intraepithelial CD8(+) T cells was significantly higher in patients alive for more than 5 years than in patients who either died of cancer after a curative operation or patients who underwent a noncurative operation. Patients' cancer-specific death long after a curative operation is thought to be caused by the growth of micrometastases in other organs or near the primary sites. The effects of intraepithelial CD8(+) T cells, therefore, may be mediated by suppression of micrometastasis, rather than suppression of growth in the primary tumour. In conclusion, our data support a hypothesis on the presence of systemic immunosurveillance against micrometastasis of cancer cells.

Adult↗

PubMed2004

Effects of a twin strain of saccharomyces cerevisiae live cells on mixed ruminal microorganism fermentation in vitro.

This experiment was designed to investigate the effects of different concentrations (0, 0.33, 0.66, 0.99, and 1.32 g/L) of a twin-strain of Saccharomyces cerevisiae live cells on in vitro mixed ruminal microorganism fermentation of corn starch, soluble potato starch, and sudangrass hay (60.5%, DM basis) plus concentrate mixture (39.5%, DM basis). Ruminal fluid was collected from two dairy cows, mixed with phosphate buffer (1:2), and incubated (30 mL) anaerobically at 38 degrees C for 6 and 24 h with or without yeast supplement, using 200 mg (DM basis) of each substrate. Medium pH, ammonia-N, and numbers of protozoa were unaffected (P = 0.38) by yeast cells in all substrates. Molar proportion of acetate was unchanged (P = 0.56) with cornstarch and soluble potato starch, but increased quadratically (P = 0.02) with hay plus concentrate by treatment. Addition of yeast cells caused a linear increase of total VFA (P = 0.008) in all substrates. Excluding the soluble potato starch, supplementation of S. cerevisiae resulted in a quadratic increase of propionate (P = 0.01), with a quadratic decrease (P = 0.04) of acetate:propionate. When soluble potato starch was used as a substrate, a linear increase (P = 0.006) of the molar proportion of propionate and a quadratic decrease (P = 0.007) in acetate:propionate was observed by treatment. Molar proportion of butyrate was unchanged (P = 0.35) with cornstarch and soluble potato starch, whereas it decreased linearly (P = 0.007) with hay plus concentrate by yeast cell supplementation. When cornstarch and soluble potato starch were used as a substrate, minor VFA were decreased (P = 0.05) by treatment. Accumulation of lactate was linearly decreased by treatment (P = 0.007) in all substrates. During incubation with hay plus concentrate, IVDMD was linearly increased (P = 0.006), whereas production of methane (linear; P = 0.02) and accumulation of hydrogen was decreased (quadratic; P = 0.005) by treatment after 24 h. These results showed that a twin strain of S. cerevisiae live cells stimulated in vitro mixed ruminal microorganism fermentation with decreased lactate, and a small decrease of methane and hydrogen with hay plus concentrate.

Ammonia↗

PubMed2004

PCR-array gene expression profiling of hepatocellular carcinoma.

Many trials using DNA microarrays have been reported for various human malignancies, but an efficient molecular diagnostic system has yet to be established. Here, we adopted a high throughput quantitative PCR-array system based on adaptor-tagged competitive PCR (ATAC-PCR), as a novel technique for gene expression profiling of hepatocellular carcinoma (HCC). This PCR-array contained 3,072 genes derived from three different cDNA libraries, including 298 additional known genes suspected to be involved in hepatocarcinogenesis. Using this PCR-array with 20 pairs of liver tissues (20 HCC, 20 surrounding nontumor liver), we identified a total of 117 genes differing in expression levels in the two liver tissues. Hierarchical clustering analysis and principal component analysis with these genes revealed distinct gene expression patterns in the HBV-positive group and the HCV-positive groups. Among 117 genes, only 7 (GPAA1, TMEM9, FACL4, ADFP, MAWBP, PACE4, FOS) were common to both groups. In conclusion, this PCR-array analysis with an appropriate set of genes is considered useful for gene expression profiling of HCC, and we identified some genes which may play a common key role in hepatocarcinogenesis.

Aged↗

PubMed2003

A new technique of thoracoscopic pleurodesis for refractory hepatic hydrothorax.

BACKGROUND: Hepatic hydrothorax is defined as a pleural effusion that arises in patients with cirrhosis of the liver and no cardiopulmonary disease; it is believed to result from peritoneopleural communication through a defect in the diaphragm. METHODS: Nine patients underwent thoracoscopic pleurodesis. The diaphragmatic defect was detected and corrected in two cases. In all patients, an argon beam coagulator was applied to the diaphragm surface, which was then completely covered with bioabsorbable prostheses. We then spread 3 ml of fibrin glue on the covered diaphragm and sprinkled 5 KE of OK-432 and 100 mg of minocycline hydrochloride in the thoracic cavity. RESULTS: All patients showed clinical improvement. The pleural effusion and breathlessness resolved immediately after pleurodesis. There were two recurrences after 1 and 4 months, respectively. One of these patients improved after repeat pleurodesis; the other was treated conservatively. CONCLUSION: Our new technique of thoracoscopic pleurodesis is an effective and minimally invasive treatment for patients with refractory hepatic hydrothorax.

Aged↗

PubMed2003

Effect of basic fibroblast growth factor on vascularization in esophagus tissue engineering.

We carried out an experimental study to evaluate the effect of basic fibroblast growth factor (bFGF)-containing collagen gel on vascularization in esophageal tissue engineering. We compared an acellular collagen sponge scaffold and an acellular collagen gel scaffold in combination with bFGF using a canine model. The construct was implanted in the cervical esophagus and the regenerated tissue was evaluated one month after surgery. Histological analysis confirmed a significantly large amount of blood vessels in the bFGF-containing collagen gel group as compared to the collagen gel group without bFGF (bFGF (-)). However, in the collagen sponge groups, no difference was observed between the bFGF (+) group and the bFGF (-) group. These results showed that bFGF-containing collagen gel is suitable not only for an acellular scaffold for tissue engineering but also for an effective tropic factor vehicle in vivo.

Animals↗

PubMed2002

Lack of effects of oxolinic acid on spermatogenesis in young adult and aged Wistar rats.

Prolonged treatment with oxolinic acid is known to elevate serum luteinizing hormone (LH) levels, resulting in induction of Leydig cell tumors in rats. In a carcinogenicity study of the compound, tubular atrophy of the testis was also increased, suggesting that oxolinic acid might affect spermatogenesis. The present study was therefore performed using rats of different ages with a particular focus on seminiferous tubule alteration and its relation to Leydig cell proliferation. Young adult (7 weeks of age) and aged (52 weeks of age) males of the Wistar strain were administered oxolinic acid at dietary concentrations of 0 (basal diet), 300, 1000 or 3000 ppm for 4 (all groups), 13 (0 and 3000 ppm groups), 26 (0 and 3000 ppm groups), or 52 weeks (0 and 3000 ppm groups of aged rats). Serum LH levels were elevated in both young adult and aged animals treated with 3000 ppm at most examined time points. While testosterone levels were also increased at the early time points in young adult, this was not the case in older animals. Elevation of the incidences of foci and/or focal hyperplasia of Leydig cells was noted but was only slight limited to aged rats treated with 3000 ppm after 26 weeks. Furthermore, it did not appear to be related to seminiferous tubular alteration. No treatment-related histopathological abnormalities could be detected in any treatment group, and morphometrical stage analysis of spermatogenesis conducted for the control and 3000 ppm-treated groups demonstrated no lesions. These results provide strong evidence that prolonged oxolinic treatment does not directly induce testicular toxicity or altered spermatogenesis in either young adult or aged rats, except for slight increase of Leydig cell proliferative lesions caused by elevated serum LH levels. Aged rats might have higher sensitivity than young adults to the effects of oxolinic acid on proliferative lesions of Leydig cells.

Aging↗

PubMed2001

Spatial and topological distribution of progesterone receptor A and B isoforms during human development.

Progesterone receptor (PR) is a member of the nuclear receptor superfamily. To date, two isoforms of PR have been identified, PR-A and PR-B. In progesterone responsive tissues, the relative ratio of PR-A and PR-B is considered to contribute to the tissue-specific actions of progesterone. In this study, we examined the distribution of PR-A and PR-B in human fetal tissues ranging from 11 to 40 gestational weeks using immunohistochemistry and RT-PCR analysis. PR immunoreactivity was detected in a wide range of fetal tissues until 20 weeks of gestation, but gradually decreased towards the late gestational period. However, PR continued to remain positive throughout the gestational period in the interstitial cells of Cajal and endocrine tissues. PR-B was demonstrated as the predominant isoform in comparison to PR-A in all fetal tissues examined. These findings suggest that progesterone may be involved in the development of fetal organs throughout the gestational period.

Embryonic and Fetal Development↗

PubMed2001

An increase in circulating mast cell colony-forming cells in asthma.

We compared a potential to generate mast cells among various sources of CD34(+) peripheral blood (PB) cells in the presence of stem cell factor (SCF) with or without thrombopoietin (TPO), using a serum-deprived liquid culture system. From the time course of relative numbers of tryptase-positive and chymase-positive cells in the cultured cells grown by CD34(+) PB cells of nonasthmatic healthy individuals treated with G-CSF, TPO appears to potentiate the SCF-dependent growth of mast cells without influencing the differentiation into mast cell lineage. CD34(+) PB cells from asthmatic patients in a stable condition generated significantly more mast cells under stimulation with SCF alone or SCF+TPO at 6 wk of culture than did steady-state CD34(+) PB cells of normal controls. Single-cell culture studies showed a substantial difference in the number of SCF-responsive or SCF+TPO-responsive mast cell progenitors in CD34(+) PB cells between the two groups. In the presence of TPO, CD34(+) PB cells from asthmatic children could respond to a suboptimal concentration of SCF to a greater extent, compared with the values obtained by those of normal controls. Six-week cultured mast cells of asthmatic subjects had maturation properties (intracellular histamine content and tryptase/chymase enzymatic activities) similar to those derived from mobilized CD34(+) PB cells of nonasthmatic subjects. An increase in a potential of circulating hemopoietic progenitors to differentiate into mast cell lineage may contribute to the recruitment of mast cells toward sites of asthmatic mucosal inflammation.

Adolescent↗

PubMed2001

Overproduction of bacterial protein disulfide isomerase (DsbC) and its modulator (DsbD) markedly enhances periplasmic production of human nerve growth factor in Escherichia coli.

Production of eukaryotic proteins with multiple disulfide bonds in the Escherichia coli periplasm often encounters difficulty in obtaining soluble products with native structure. Human nerve growth factor beta (NGF) contains three disulfide bonds between nonconsecutive cysteine residues and forms insoluble aggregates when expressed in E. coli. We now report that overexpression of Dsb proteins known to catalyze formation and isomerization of disulfide bonds can substantially enhance periplasmic production of NGF. A set of pACYC184-based plasmids that permit dsb expression under the araB promoter were introduced into cells carrying a compatible plasmid that expresses NGF. The efficiency of periplasmic production of NGF fused to the OmpT signal peptide was strikingly improved by coexpression of DsbCD or DsbABCD proteins (up to 80% of total NGF produced). Coexpression of DsbAB was hardly effective, whereas that of DsbAC increased the total yield but not the periplasmic expression. These results suggest synergistic roles of DsbC and DsbD in disulfide isomerization that appear to become limiting upon NGF production. Furthermore, recombinant NGF produced with excess DsbCD (or DsbABCD) was biologically active judged by the neurite outgrowth assay using rat PC12 cells.

Animals↗

PubMed2001

Chronic exposure to ELF magnetic fields during night sleep with electric sheet: effects on diurnal melatonin rhythms in men.

The possible effects of repeated night-time exposure to an extremely low frequency magnetic field (ELF-MF) on melatonin were investigated in nine healthy male subjects aged 23-37 yr. The 16-week experiment consisted of 3 weeks of pre-exposure, 11 weeks of night-time exposure to MF generated from a nonheated electric sheet (ES), and 2 weeks of post-exposure recovery observation. The average MF intensity (rms, mainly 50 Hz AC) on the surface of the sheet was 0.7 microT at the head, 8.3 microT at the waist, and 3.5 microT at the feet of the subject. For each of the urine samples collected 5 times a day on scheduled sampling days, the urinary excretion rate (ng/h) of melatonin was determined, and 24 h rhythms were extracted for each subject and each experimental period (pre-exposure, first half and latter half exposure, and post-exposure periods) by the method of complex cosine curve fitting. Although estimates of the peak height, acrophase, and total daily amount of melatonin were characterized by significant variations among individual subjects, they did not reveal any statistically significant difference between exposure periods and nonexposure periods. Thus, the present study indicates that any profound effect of the MF originating from an ES on nocturnal melatonin production and its circadian rhythm is unlikely.

Adult↗

PubMed2001

Thoracoscopic lung volume reduction surgery for pulmonary emphysema patients with severe hypercapnia.

OBJECTIVES: We assessed whether hypercapnia patients with an extremely high level of PaCO2 > or = 60 mmHg were suitable candidates for lung volume reduction in the treatment of severe pulmonary emphysema. METHODS: Of 65 patients undergoing lung volume reduction surgery between May 1993 and August 1997, 6 (9.23%) who had a preoperative rest room air blood gas level of PaCO2 > or = 60 mmHg were selected for study. All patients underwent video-assisted thoracoscopic surgery. Of the 6 with severe hypercapnia, 5 underwent the unilateral procedure and 1 the bilateral procedure. RESULTS: All severe hypercapnia patients showed significant clinical improvement. When assessed at 3 to 6 months after lung volume reduction surgery, significant improvements were seen in mean forced expiratory volume in 1 second (preop: 0.44 +/- 0.04 L; postop: 0.74 +/- 0.20 L; p < 0.01), for a magnitude improvement of 69.8%, and in trapped gas volume (preop: 3.28 +/- 1.11 L; postop: 1.61 +/- 1.02 L; p < 0.05). Arterial blood gas analysis showed significant improvement in PaO2 from 51.1 +/- 6.68 mmHg to 69.8 +/- 7.87 mmHg (p < 0.001) with a decrease in PaCO2 from 70.4 +/- 9.41 mmHg to 46.9 +/- 3.44 mmHg (p < 0.01). Postoperative follow-up averaged 55 months (43-69 months). All but 1 patient remain alive and well. CONCLUSION: Patients with severe pulmonary emphysema accompanied by hypercapnia can gain relief and a better quality of life through volume reduction surgery and should not be excluded from surgical treatment simply based on this condition. Selection should involve a comprehensive view of the patient's condition that includes criteria such as the results of radiographic diagnosis and detailed pulmonary function tests.

Aged↗

PubMed2001

Butylhydroxytoluene (BHT) increases susceptibility of transgenic rasH2 mice to lung carcinogenesis.

PURPOSE: Transgenic mice carrying the human prototype c-Ha-ras gene (rasH2 mice) are highly susceptible to lung carcinogens. In order to investigate the possibility of developing a rapid in vivo assay for lung carcinogens, we examined whether the tumor-promoting activity of butylhydroxytoluene (BHT) is efficacious in rasH2 mice. METHODS: rasH2 mice and wild littermates of both genders were pre-treated with carcinogens [urethane (UR), 4-nitroquinoline 1-oxide (4NQO) or diethylnitrosamine (DEN)], and, one day later, given a 400 mg/kg dose of BHT. RESULTS: Six weeks after the initiation treatment, evidence of carcinogenicity could be detected in male and female rasH2 mice that had received UR doses of > or = 250 mg/kg and > or = 125 mg/kg, respectively, prior to exposure to BHT, whereas only 500 mg/kg of UR was sufficient to induce tumors in female rasH2 mice given the carcinogen alone. The carcinogenicity of 15 mg/kg of 4NQO could be detected after 9 weeks in male rasH2 mice given the carcinogen followed by BHT. Similarly, the carcinogenicity of 60 mg/kg of DEN could be detected after 9 weeks and 6 weeks, respectively, in male and female rasH2 mice given the carcinogen followed by BHT. No carcinogenicity could be demonstrated through the experimental period with doses of 4NQO or DEN given alone. CONCLUSIONS: These results indicate that BHT administration increases the susceptibility of rasH2 mice to lung carcinogens, and suggest that the use of BHT in rasH2 mice might lead to the establishment of a rapid in vivo assay for lung carcinogens.

Adenocarcinoma↗

PubMed2001

A collision tumor composed of adenocarcinoma and malignant lymphoma in the remnant stomach after pancreatoduodenectomy: report of a case.

The occurrence of a collision tumor in the stomach, consisting of adenocarcinoma and malignant lymphoma, is extremely rare. We report herein the case of a patient who had undergone a pancreatoduodenectomy for bile duct cancer 5 year earlier, in whom an ulcerating tumor of the remnant stomach developed and grew rapidly within 5 months. Surgical exploration revealed a tumor in the remnant stomach, multiple liver metastases, and multiple lymph node metastases. Total resection of the remnant stomach was performed, and pathological examination revealed a collision tumor consisting of adenocarcinoma and malignant lymphoma. The patient died of liver metastases and lymph node metastases 7 months after his second operation. The coexistence of both adenocarcinoma and malignant lymphoma of the remnant stomach and the etiology of this unusual combination, never previously reported, is discussed.

Adenocarcinoma↗

PubMed2001

Characteristics of aneurysms arising from the horizontal portion of the anterior cerebral artery.

BACKGROUND: Aneurysms arising from the proximal portion of the anterior cerebral artery (A1: horizontal portion) are quite rare and are considered to be unique, because they are usually connected with other vascular anomalies and are sometimes part of a multiple aneurysm occurrence. A1 aneurysm cases experienced over the past seven and a half years are summarized in this paper. METHODS: A total of 413 patients were surgically treated including 142 patients with subarachnoid hemorrhage (SAH); the remaining 271 patients had unruptured aneurysms. Among them, nine cases were categorized as constituent A1 aneurysms, three with SAH and six with unruptured aneurysms. RESULTS: The shape of the aneurysm was saccular in all nine cases. Three of the nine cases had associated vascular malformations. The average aneurysm diameter in the three cases with SAH was 4.0 mm, which is smaller than other common aneurysms presenting with SAH. Eight aneurysms developed at the takeoff point of perforating arteries-the medial lenticulostriate artery in five cases and the recurrent artery of Heubner in three cases. In the remaining case, the aneurysm originated from the proximal end of the associated A1 fenestration. All nine patients had an excellent outcome after surgery. CONCLUSION: A1 aneurysms require surgical elimination even if they are small. We emphasize the importance of preserving the blood flow of these perforating arteries by avoiding compression with either the clip blade or the clip body itself.

Adult↗

PubMed2001

Oxidative folding of human lysozyme: effects of the loss of two disulfide bonds and the introduction of a calcium-binding site.

Mutant human lysozymes (HLZ) lacking two disulfide bonds were constructed to study the importance of each disulfide bond on oxidative refolding. To avoid destabilization, a calcium-binding site was introduced. Five of the six species of two-disulfide mutants could be obtained with enzymatic activity. Based on the information obtained from refolding and unfolding experiments, the order of importance in oxidative refolding was found to be as follows: SS2(Cys30-Cys116) > SS1(Cys6-Cys128) approximately SS3(Cys65-Cys81) > SS4(Cys77-Cys95). Without SS2, these mutants refolded with low efficiency or did not refold at all. The bond SS2 is located in the interface of B-and D-helices, and a small hydrophobic cluster is formed near SS2. This cluster may play an important role in the folding process and stabilization, and SS2 may act as a stabilizer through its polypeptide linkage. The bond SS2 is the most important disulfide bond for oxidative folding of lysozymes.

Binding Sites↗

PubMed2001

A possible role for maternal HLA antibody in a case of alloimmune neonatal neutropenia.

BACKGROUND: Alloimmune neonatal neutropenia (ANN) is caused by a reaction of maternal alloantibodies with paternally inherited antigens on the fetal neutrophils. While human neutrophil antigens (HNA) antibodies are found in half of ANN cases, specific antibodies have not been defined in the remaining cases. STUDY DESIGN AND METHODS: Reported here is a neonate with omphalitis due to neutropenia. To elucidate the cause of ANN, flow cytometric and PCR analyses were used. Reactions of the patient's and mother's sera with neutrophils, lymphocytes, and platelets were examined by lymphocytotoxicity test (LCT), anti-human immunoglobulin-LCT, and mixed passive hemagglutination test. RESULTS: The maternal sera reacted with neutrophils, lymphocytes, and platelets of the patient and father. The platelet adsorption eliminated the reaction of the maternal serum with the patient's neutrophils. The HLA typing of the family and an LCT using a panel of lymphocytes of 20 HLA-typed donors showed HLA-A2 antigen as a target of antibodies in the maternal serum. According to anti-human immunoglobulin-LCT, the anti-HLA-A2 was present in the neonatal serum. On the other hand, HNA antibodies were not detectable in the patient's or the mother's serum. CONCLUSION: These results suggest that the transplacental passage of the maternal HLA antibody caused neutropenia in this patient.

Adult↗

PubMed2001

Surgical strategy for cavernous angioma in hypothalamus.

A very rare case of cavernous angioma in the hypothalamus is presented. The patient was successfully treated by total excision of the haematoma and angioma, and there was no regrowth of the lesion on follow-up MRI. Complete excision of the angioma is the recommended surgical strategy even for patients with deep-seated lesions.

Adult↗