Biomedical subjects

Y Kurokawa

Publications and source records attributed to Y Kurokawa.

At least 19 recordsLinked to original sources

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↗

PubMed2001

The successful management of thoracoscopic thoracic duct ligation in a compromised infant with targeted lobar deflation.

IMPLICATIONS: We describe the successful management of thoracoscopic thoracic duct ligation in a 2.5-kg compromised infant by using selective lobar-bronchial blockade. The technique reduces the risk of intraprocedural physiologic impairment, allowing the benefits of otherwise minimally invasive thoracoscopic procedures, even when the conditions of children are severely compromised.

Chylothorax↗

PubMed2001

New method for obliterative treatment of an anterior wall aneurysm in the internal carotid artery: encircling silicone sheet clip procedure--technical case report.

OBJECTIVE AND IMPORTANCE: Aneurysms on the anterior surface of the internal carotid artery (ICA) have been shown to be somewhat different from ordinary berry aneurysms because they are rather small, grow rapidly in a short time, and easily lead to rupture, especially during surgery. The most difficult problem is that this type of aneurysm cannot be eliminated easily by an ordinary clipping procedure without causing apparent arterial stenosis or occlusion. CLINICAL PRESENTATION: A 52-year-old man experienced a subarachnoid hemorrhage because of a ruptured aneurysm located on the anterior surface of the ICA. The tiny aneurysmal body, which was covered with a layer of brain tissue, was successfully exposed. The ICA seemed to be atherosclerotic, and the aneurysmal portion was solitary and had a reddish color. TECHNIQUE: A large silicone sheet encircling clip (Vascwrap; Mizuho Ikakogyo Co., Ltd., Tokyo, Japan) was selected for this patient. The proximal margin of the silicone sheet was incised with a V-shaped cut, and the middle part of the sheet, which covered the diagonal part of the ICA, was trimmed to make it shorter. The blade of the fenestrated clip was applied to obliterate the aneurysm and was attached to the normal arterial wall together with this modified Vascwrap sheet to create a small space between the normal arterial wall and the surrounding Vascwrap sheet. Then tiny pieces of Teflon fiber (E.I. duPont de Nemours and Co., Wilmington, DE) was inserted from both margins, and the whole Vascwrap sheet was sealed with fibrin glue to ensure good adhesion. CONCLUSION: This method seemed adequate in treating this difficult aneurysm without causing postoperative regrowth or occlusion of the patient's ICA.

Carotid Artery, Internal↗

PubMed2001

Video-assisted thoracoscopic surgery for catamenial hemoptysis.

Catamenial hemoptysis is a rare condition, and only 36 cases have been reported since the first published case. We describe a woman with catamenial hemoptysis recurring over 8 years. The lesion was diagnosed using chest CT scan during menses and was also visualized clearly via thoracoscopy. The patient was treated successfully with a partial resection of the lung using video-assisted thoracic surgery (VATS) and has been asymptomatic for 14 months since the operation. We suggest that VATS for catamenial hemoptysis is a more effective treatment than medical therapy.

Adult↗

PubMed2001

Brain hypothermia relieves severe brain swelling following acute major cerebral artery occlusion.

Seven patients were treated with brain hypothermia following acute major cerebral artery occlusion to utilize the suppressive effect against brain swelling. Five patients had internal carotid and two had proximal middle cerebral artery occlusion. Except for the first two cases, hypothermia was introduced early and the temperature reached 35.0 degrees C within 6 hours after the onset. The core temperature finally stabilized between 32 degrees C to 34 degrees C. Hypothermia had a suppressive effect against brain swelling and the temperature showed a significant correlation to intracranial pressure. Recurrence of brain swelling was observed during the rewarming process, but two patients became independent and three patients were moderately disabled in wheelchairs. Only two patients died. Brain hypothermia is an effective treatment for acute major cerebral artery occlusion through the relief of brain swelling. The overall outcome may be improved by combining brain hypothermia with other conventional therapies such as osmotherapy and external decompression implemented with an extended period of rewarming.

Acute Disease↗

PubMed2001

[Fukuronori (Gloiopeltis furcata) extract: 90-day dietary toxicity study in F344 rats].

Fukuronori extract (FE), which is mainly composed of polysaccharides, and is an extract of the seaweed Gloiopeltis furcata, is permitted for use as a food thickening agent by the Ministry of Health and Welfare, Japan. In order to study the subchronic toxicity of FE, F344 rats of both genders were administered FE at concentrations of 0% (basal diet, control group), 0.5%, 1.5% and 5.0% in basal powder diet for 90 days, and observation of general condition, recording of body weight and food consumption, examination of hematology and blood chemistry, measurement of organ weight, and pathological examination were performed. Food consumption tended to increase in both sexes given FE at 1.5% and 5.0% throughout most of the experimental period. This was, however, considered not to be a toxic effect because the differences in body weight were small. Total cholesterol and triglycerides in serum decreased significantly (p < 0.05) and not significantly, respectively, in males of the 5.0% group. These changes were considered to be related to the intake of FE, but the differences were slight and within physiological ranges. Hematological and pathological examination revealed neither any particular adverse effect nor any significant difference from the control. Hence, dietary intake of 5.0% of FE, 3,362 mg/kg/day for males and 3,594 mg/kg/day for females as mean daily intake, for 90 days was considered to be a no observable adverse effect level in rats.

Algorithms↗

PubMed2001

[A case of tuberculosis of the prostate presenting as endoscopically cavitary change].

A 62-year-old man was admitted to our hospital with the chief complaint of terminal macroscopic hematuria. He had a history of left tuberculous epididymitis in 1994. On digital rectal examination, the prostate was found to be a normal size and slightly hard with no elasticity. Transcrectal ultrasound showed hypoechoic lesions in the peripheral zone. T1-weighted MRI demonstrated cavitary lesions and T2-weighted MRI demonstrated relatively low signal intensity in the same zone. Urethrography revealed various cystlike lesions in the prostatic urethra. Cystourethroscopy revealed cavitary change with many septa in the left lobe of the prostate. TUR-P was performed and histological findings of the specimen revealed tuberculosis of the prostate. The patient was treated with an antituberculous regimen of INH, RFP and EB.

Endoscopy↗

PubMed2001

Tissue engineering of the small intestine by acellular collagen sponge scaffold grafting.

Tissue engineering of the small intestine will prove a great benefit to patients suffering from short bowel disease. However cell seeding in tissue engineering, such as fetal cell use, is accompanied by problems of ethical issues, rejection, and short supply. To overcome these problems, we carried out an experimental study on tissue engineering of the small intestine by acellular collagen sponge scaffold grafting. We resected the 5 cm long jejunum from beagle dogs and reconstructed it by acellular collagen sponge grafting with a silicon tube stent. The graft was covered with the omentum. At 1 month after operation, the silicon stent was removed endoscopically. Animals were sacrificed 1 and 4 months after operation, and were examined microscopically. Neo-intestinal regeneration was observed and the intestinal mucosa covered the luminal side of the regenerated intestine across the anastomosis. Thus, the small intestine was regenerated by tissue engineering technology using an acellular collagen sponge scaffold.

Animals↗