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Biomedical subjects

I Ishida

Publications and source records attributed to I Ishida.

At least 37 records · Page 2Linked to original sources
PubMed2000

Manipulation of human minichromosomes to carry greater than megabase-sized chromosome inserts.

For introducing regions of human chromosomes greater than a megabase into cells or animals, we have developed a chromosome-cloning system in which defined regions of human chromosomes can be cloned into a stable human minichromosome vector in homologous recombination-proficient chicken DT40 cells. The stable minichromosome vector allowed a 10 Mb-sized region of the mitotically unstable human chromosome 22 to be stably maintained in mouse embryonic stem (ES) cells, and in mice. Furthermore, we demonstrated functional expression of human genes from the HAC in mice. This study describes a stable cloning and expression system for greater than megabase-sized regions of human chromosomes.

Animals↗
PubMed2000

[Successful treatment for descending necrotizing mediastinitis: a case report].

A 21-year-old female was admitted to our hospital because of high fever, neck swelling, and dyspnea. She was diagnosed as descending necrotizing mediastinitis (DNM) extended from odontogenic infection. On the day of admission, she underwent cervical drainage. Next day, the CT scan showed an abscess below the tracheal bifurcation and bilateral pleural effusion. Mediastinal drainage was performed through a right thoracotomy, and a left thoracic tube was inserted. Anaerobic Peptostreptococcus was found with bacteriological culture. After the mediastinal drainage, bilateral thoracic irrigation was performed through the thoracic tubes. Left thoracic tube was removed on the 8th day and right one was removed on the 20th day after the thoracotomy. She was discharged on the 42nd day. DNM is relatively rare, but it is lethal disease with high mortality. Immediate and sufficient mediastinal drainage is indispensable for the disease.

Abscess↗
PubMed2000

Optimal hematocrit for the maximum oxygen delivery to the brain with recombinant human erythropoietin in hemodialysis patients.

AIM: Although hematocrit (Ht) around 33 to 36% has been recommended, Ht of 30% is usually achieved as a target level during recombinant human erythropoietin (rHuEPO) therapy in the majority of hemodialysis (HD) patients. The present study aimed at estimating an optimal hematocrit (Ht) for the maximum oxygen delivery to the brain with rHuEPO. PATIENTS AND METHODS: Oxygen delivery was defined as a product of cerebral blood flow and arterial oxygen content (CaO2). The regional cerebral blood flow (rCBF) in each region of interest was measured by positron emission tomography and CaO2 was calculated from hemoglobin concentration, arterial oxygen saturation, and arterial oxygen tension before and after rHuEPO therapy (1,500 units, 3 times a week) in 5 HD patients (the mean age of 52 +/- 2 (SEM) years old and the mean HD duration of 98 +/- 21 months). RESULTS: Ht rose significantly from 21 +/- 1 to 31 +/- 1% (p < 0.001) after the 3-month rHuEPO treatment in association with a significant increase in CaO2 from 7.7 +/- 0.4 to 11.6 +/- 0.3 ml O2/100 ml (p < 0.01). Hemispheric rCBF decreased significantly from 40 +/- 3 to 32 +/- 1 ml/100 g/min (p < 0.02). In all data both before and after rHuEPO treatment, Ht inversely correlated with the hemispheric rCBF (y = 55.7 - 0.76x, where y is rCBF and x is Ht, r = 0.80, p < 0.01), and positively with CaO2 (y = 0.85 + 0.34x, where y is CaO2 and x is Ht, r = 0.95, p < 0.01). By using these correlations, the hemispheric oxygen delivery was expressed as a function of Ht, being y = 47.3 + 18.3x - 0.3 x2, where y is cerebral oxygen delivery and x is Ht. From this curve, Ht at the highest cerebral oxygen delivery in the hemisphere, i.e. an optimal Ht was found to be 35.2%. Above this level of Ht, the hemispheric cerebral oxygen delivery would rather decline. CONCLUSION: The present study indicated that Ht of about 35% is required for a better oxygen delivery to the brain metabolism during anemia correction with rHuEPO.

Anemia↗
PubMed1999

Hemodialysis causes severe orthostatic reduction in cerebral blood flow velocity in diabetic patients.

Orthostatic hypotension is a serious problem in patients with diabetes mellitus (DM) undergoing hemodialysis (HD). To evaluate cerebral circulation during orthostasis in patients with DM, we examined changes in mean blood flow velocity in the middle cerebral artery (VMCA) during 60 degrees head-up tilt for 5 minutes in patients with DM (six men, two women; age, 57 +/- 3 years [mean +/- SEM]; HD duration, 47 +/- 27 months) before and after bicarbonate HD by using transcranial Doppler sonography. The findings were compared with those in HD patients without diabetes (non-DM; 12 men, 5 women; age, 47 +/- 3 years; HD duration, 82 +/- 23 months). Mean blood pressure (MBP) in the supine position, hematocrit (Hct), plasma fibrinogen, and volume of fluid removed by HD were not significantly different between the two groups (MBP, 106 +/- 6 versus 103 +/- 4 mm Hg; Hct, 26% +/- 1% versus 28% +/- 1%; fibrinogen, 355 +/- 37 versus 357 +/- 27 mg/dL; fluid, 2.5 +/- 0.2 versus 2.3 +/- 0.2 L). Percentage of change in VMCA (% VMCA) during tilt was compared between the groups before and after HD. Before HD, MBP decreased significantly to 93 +/- 5 mm Hg during tilt only in patients with DM. The degree of MBP reduction was -13 +/- 2 mm Hg in DM and -2 +/- 2 mm Hg in non-DM patients (P < 0.01). % VMCA equally decreased during tilt; DM, -12% +/- 3%, and non-DM, -12% +/- 2%. After HD; MBP decreased by 36 +/- 7 mm Hg in patients with DM, which was significantly greater than before HD. VMCA also decreased in both groups after HD, and % VMCA in DM (-32% +/- 5%) was significantly greater than before HD (P < 0.01) and in non-DM patients (-13% +/- 2%; P < 0.01). % VMCA positively correlated with the percentage of change ratio of MBP during tilt in both groups after HD (DM, r = 0. 87, P < 0.01; non-DM, r = 0.61, P < 0.01). Our results showed a significant decrease in cerebral blood flow velocity during tilt of equal magnitude in both groups before HD despite differences in the level of hypotension, whereas reduction in cerebral blood flow velocity and decrease in MBP were more marked in DM after HD. Orthostasis could thus cause hemodynamically mediated brain damage after HD, especially in patients with DM.

Aged↗
PubMed1998

Efficient modification of a human chromosome by telomere-directed truncation in high homologous recombination-proficient chicken DT40 cells.

Truncation of human chromosomes at desired sites by homologous recombination techniques enables functional and structural analyses of human chromosomes and development of human artificial chromosomes. However, this targeted truncation has been inefficient. We describe here an efficient method for targeted truncation in the chicken DT40 cells with a high homologous recombination rate. The human chromosome 22 was transferred into DT40 cells, where human telomeric repeat (TTAGGG)n was targeted to the LIF locus on the chromosome. Molecular and cytogenetic analyses showed that the predicted truncation at the LIF locus occurred in all of the targeted clones.

Animals↗
PubMed1998

The status of human papillomavirus and tumor suppressor genes p53 and p16 in carcinomas of uterine cervix from India.

OBJECTIVES: Infection with the high-risk strain of human papillomaviruses (HPVs) and the inactivation of the tumor suppressor gene p53 through mutation are important factors in cervical carcinogenesis. To know whether such events would occur in cervical carcinomas of Indians, 43 tumors (consisting of 36 of stage III B and 6 of stage II B) were screened for p53 and p16 gene mutations. METHODS: PCR followed by single-strand conformation polymorphism (SSCP) analysis were used to detect mutations in p53 and p16 genes and PCR for the presence of human papillomavirus genome. HPV status was ascertained by PCR amplification of parts of E6 and E7 genes using primers pU-1M and pU-2R and typing was carried out by restriction analysis. RESULTS: Of the 43 samples analyzed, 4 samples (9%) showed mobility shifts for p53 mutations; PCR products of the p16 gene did not show band shifts in SSCP analysis. HPV DNA was detected in 70% of the 43 samples analyzed: HPV 16 in 23 cases (53%), HPV 18 in 4 cases (13.3%), and HPV 33 in 1 case (3.3%). Two amplified HPV DNAs that were difficult to type with various restriction enzymes were cloned and the amplified regions were sequenced. One of these was 93% close to HPV 35 and the other was 80% close to HPV 58. Three samples had both p53 mutations and HPV genome. CONCLUSIONS: Our results indicate that HPV 16 infection was more common than HPV 18, the p53 mutations and HPV infection were not mutually exclusive events in the genesis of carcinoma of uterine cervix among Indian women, and p16 gene may not play a role in Indian cervical carcinomas.

Adult↗
PubMed1998

[An operative case of primitive neuroectodermal tumor in the posterior mediastinum].

A primitive neuroectodermal tumor (PNET) is very rare and the prognosis of this tumor is poor. A 32-year-old woman complaining of dysphagia and back pain was admitted to our hospital for the posterior mediastinal tumor. The tumor originated from the muscle layer of esophagus and en bloc resection of the tumor combined with the affected part of esophagus was performed. Histopathological diagnosis of the resected tumor was PNET. She received adjuvant chemotherapy. Eight months after the surgery, recurrent tumors in the right mediastinum and the retrooperitoneal space was resected completely. But after the second surgery, dissemination occurred recurrently. These recurrent tumors revealed high sensitivity for radio-therapy. However, she died of rapid recurrence 22 months after the first surgery. In Japan, our case is the second case of PNET in the posterior mediastinum and the first case of PNET arising from the muscle layer of esophagus.

Adult↗
PubMed1998

[The relationship between the pathways of the lymphatic drainage into the mediastinal nodes and the survival rate for N2 lung cancers underwent curative resection].

The pathways of the metastases to the mediastinal nodes were determined in each case of 68 N2 lung cancer patients undergoing mediastinal lymph node dissection. The relationship between the pathways of the metastases and the survival rate was examined in the 57 N2 lung cancer patients undergoing curative resection. The results were as follows: (1) The direct metastatic passage to the mediastinal nodes was observed in 32.1% in the right upper lobe. The survival rate of this group was 55.4% (4-year survival rate), and that of cases metastasized to the intrapulmonary and/or hilar nodes as well as mediastinal nodes was 42.4% (3-year survival rate). (2) The dominant lymphatic drainage from the middle lobe and the lower lobes flowed into the subcarinal nodes through the hilar nodes. 75% had involvement of the subcarinal nodes, and 33.3% had involvement of the upper mediastinal nodes. 5-year survival rate of the cases without the upper mediastinal nodes metastases was 59.0%, and that of cases metastasized to the upper mediastinal nodes was 26.7% (3-year survival rate). (3) The dominant lymphatic drainage from the left upper lobe flowed into the subaortic or paraaortic nodes. 5-year survival rate in the left upper lobe was 50.0%. It suggested that the cases metastasized to the mediastinal nodes via the direct passage in the right upper lobe, the cases in the left upper lobe, and the cases metastasized to the subcarinal nodes without the upper mediastinal nodes metastases in the middle lobe and the lower lobes had better prognosis.

Humans↗
PubMed1998

[A case of pulmonary arteriovenous fistula beneath the surface of the lung].

A 19-year-old woman complaining of exertional dyspnea was admitted to our hospital with an abnormal shadow on the left side of the chest. Laboratory examination revealed polycythemia and hypoxemia. Pulmonary angiogram demonstrated a pulmonary arteriovenous fistula beneath the surface of the left S10. Partial resection of the left S10 was performed. The wall of the arteriovenous fistula was flimsy and seemed to rupture easily. The sister of this patient also had a peripheral pulmonary arteriovenous fistula and suffered from repeating epistaxis. Rendu-Osler-Weber disease was diagnosed in both, and the sister underwent partial resection of the right S7, which contained the fistula. Their postoperative courses were uneventful. Hemothorax and hemoptysis are lethal complications of arteriovenous fistulae. In order to avoid the rupture of fistulae, surgical resection is the most reliable treatment. Pulmonary arteriovenous fistulae beneath the surface of the lung should be resected.

Adolescent↗
PubMed1998

[Two cases of solitary peripheral pulmonary arterial aneurysm].

We report two very rare cases of solitary peripheral pulmonary arterial aneurysm. Case 1: An 83-year-old man treated for myocardial infarction died of multiple organ failure and hemoptysis. Autopsy disclosed rupture of a pulmonary arterial aneurysm 1.5 cm in diameter in the right A3. Case 2: A 75-year-old man was found to have a pulmonary arterial aneurysm, 3 cm in diameter of the right A1. Surgical treatment was not indicated, because of severe pulmonary emphysema. The aneurysms in these two cases were idiopathic: (1) there were no histologic findings that would implicate specific chronic inflammation. (2) the period from the occurrence of secondary pulmonary hypertension to hemoptysis was short, and there was no (3) history of trauma.

Aged↗
PubMed1997

The structure and function of a soybean beta-glucan-elicitor-binding protein.

beta-Glucan elicitor (GE), released from the cell wall of the phytopathogenic fungus Phytophthora megasperma by soybean glucanases, causes defense reactions in soybean. A GE-binding protein (GEBP) was purified from the membrane fraction of soybean root cells, and its cDNA was isolated. Expression of the cDNA clone in tobacco suspension cultured cells and in Escherichia coli conferred GE-binding activity to both. An antibody against the recombinant protein was found to inhibit the GE binding with the soybean cotyledon membrane fraction as well as the resulting accumulation of phytoalexin. Immunolocalization assays indicated that the GEBPs are located in the plasma membrane of root cells. These results suggest that the cDNA encodes a GE receptor and may mediate the signaling of the elicitor.

ATP-Binding Cassette Transporters↗
PubMed1997

Transgenic potato expressing a double-stranded RNA-specific ribonuclease is resistant to potato spindle tuber viroid.

We have produced transgenic potato lines expressing the yeast-derived double-stranded RNA-specific ribonuclease pac1. Five lines of pac1 potato (Solanum tuberosum L., cultivar Russet Burbank) challenged with potato spindle tuber viroid (PSTVd) suppressed PSTVd infection and accumulation. All of the progeny potato tubers produced by resistant plants were also free of PSTVd. Because the pac1 gene product digested PSTVd in vitro, double-stranded regions in PSTVd molecule and/or replicative intermediates may be targeted by pac1 gene product in the transgenic potato plant.

Endoribonucleases↗
PubMed1997

Functional expression and germline transmission of a human chromosome fragment in chimaeric mice.

Human chromosomes or chromosome fragments derived from normal fibroblasts were introduced into mouse embryonic stem (ES) cells via microcell-mediated chromosome transfer (MMCT) and viable chimaeric mice were produced from them. Transferred chromosomes were stably retained, and human genes, including immunoglobulin (Ig) kappa, heavy, lambda genes, were expressed in proper tissue-specific manner in adult chimaeric tissues. In the case of a human chromosome (hChr.) 2-derived fragment, it was found to be transmitted to the offspring through the germline. Our study demonstrates that MMCT allows for introduction of very large amounts of foreign genetic material into mice. This novel procedure will facilitate the functional analyses of human genomes in vivo.

Animals↗
PubMed1997

[A case of successful treatment with ganciclovir for cytomegalovirus pneumonia after pulmonary lobectomy].

The premortem diagnosis of cytomegalovirus (CMV) pneumonia is usually difficult, and mortality of it is high. A case of successful treatment with ganciclovir for cytomegalovirus pneumonia after pulmonary lobectomy is reported. The patient was a 76-year-old man. Under diagnosis as lung cancer, the right lower lobectomy was performed. After operation, pneumonia occurred on the nonoperated side and in a few days reticular shadows rapidly spread to the whole lung. Although pulse steroid therapy was performed, the interstitial pneumonitis improved only a little. Then intranuclear inclusion body-bearing giant cells were found in sputum obtained by bronchoscopy. So we diagnosed the interstitial pneumonitis as CMV pneumonia and ganciclovir was administrated. CMV pneumonia had improved for two weeks and the patient has no recurrence. When interstitial pneumonitis develop in patients after operation or steroid therapy, the differential diagnosis should include the possibility of CMV pneumonia.

Aged↗
PubMed1996

Virus-induced cell death in plants expressing the mammalian 2',5' oligoadenylate system.

The major components of the 2-5A system, responsible for the mammalian interferon-induced antiviral response, are the 2',5' oligoadenylate synthetase (2-5Aase) and 2',5' oligoadenylate (2-5A) dependent ribonuclease (RNase L). Transgenic tobacco plants expressing these two enzyme activities were produced by crossing the transgenic plants expressing RNase L with those expressing 2-5Aase. The double transgenic plants showed complete resistance against cucumber mosaic virus (CMV), infection with necrotic spots only forming on the virus-inoculated leaf. On the other hand, although plants inoculated with potato virus Y (PVY) formed necrotic spots on the inoculated leaf and virus amplification could not be detected, all plants died within 20 days of inoculation. The transgenic tobacco plants expressing either 2-5Aase or RNase L activity showed typical disease symptoms with CMV- or PVY-inoculation. These results suggest that the introduced 2-5A system is activated in tobacco cells by dsRNA, the replicating intermediates of RNA viruses, leading to death of the host cells, which has not been observed in mammalian cells.

Adenine Nucleotides↗
PubMed1996

Steroid-resistant nephrotic syndrome associated with malignant thymoma.

Two patients with malignant thymoma of lymphoepithelial cell type developed nephrotic syndrome and irreversible acute renal failure 18 months after the radiation therapy. Repeated renal biopsies revealed focal segmental glomerulosclerosis (FSGS) in both cases (a 66-year-old female and a 82-year-old female). Several immunological disorders were found, being a presence of autoantibodies such as antinuclear antibody, anti-acetylcholine receptor antibody, antistriatal antibody and an elevation of serum IgM. In both cases the nephrotic syndrome was resistant to corticosteroid as well as cyclophosphamide. Renal dysfunction eventually progressed to end-stage renal failure requiring regular hemodialysis treatment. A sustained immunological impairment related to the residual malignant thymoma was considered to be of pathogenic importance for the delayed occurrence of nephrotic syndrome. Fifteen thymoma cases with nephrotic syndrome from the previous reports are also reviewed.

Aged↗