Search PubMed⌕ Search

Biomedical subjects

K Iwai

Publications and source records attributed to K Iwai.

At least 163 records · Page 9Linked to original sources
PubMed1991

[Clinical and pathologic features of rounded atelectasis in patients with empyema].

Rounded atelectasis (RoA) is an uncommon pulmonary condition presenting as a peripheral round opacity on a chest roentgenogram. Six cases of empyema who underwent regional lung and pleural resection, had local atelectatic induration beneath the pleura. Their clinical and pathologic features were examined. Five cases had past histories of pulmonary tuberculosis with therapeutic pneumothorax, and one other case had tuberculous pleuritis. Five of seven atelectatic indurations displayed RoA on preoperative plain radiography ++ and/or CT and on soft X-ray films of resected lung preparations. With pathological examinations, the pleura showed one or several indentations, often with deep invaginations into the pulmonary parenchyma. In these regions, the appearance was occasionally more complex due to several small folds emanating from the larger fold. Outside the pleural folds, there was dense fibrous thickening. Fibrosis of the pleural interstitial layer itself was mild. Lung parenchyma adjacent to the folded pleura appeared collapsed with mild interstitial fibrosis. These findings lead to the hypothesis that RoA may result from pleural invaginations occuring after pleural effusion or therapeutic pneumothorax and from fibrous adhesions of the outer regions.

Aged↗
PubMed1990

A case of Fabry's disease in a patient with no alpha-galactosidase A activity caused by a single amino acid substitution of Pro-40 by Ser.

We analyzed a male patient with Fabry's disease who had no activity of the lysosomal hydrolase alpha-galactosidase A (alpha-GalA) and female members of his family. We cloned a cDNA that encoded the mutant alpha-GalA, determined its nucleotide sequence, and found two nucleotide differences between the mutant and the wild-type cDNAs. Although one difference was silent, the other difference, a C-to-T transition at nucleotide number 118, resulted in an amino acid substitution of Pro-40 by Ser. A transient expression assay demonstrated that this missense mutation was the cause of the deficiency of alpha-GalA activity in the patient. In vitro mutagenesis experiments demonstrated that Pro-40 is critical for the appearance of alpha-GalA activity.

Base Sequence↗
PubMed1990

Significance of the contribution of aerobic and anaerobic components to several distance running performances in female athletes.

To assess the most important determinant for successful distance running (800 m, 1500 m and 3000 m events) in female athletes, measurements of several anaerobic indices were made (peak power, mean power) using the Wingate anaerobic test (WAnT), and aerobic indices such as oxygen uptake (VO2) or running velocity (v) at lactate threshold (LT), VO2 or v at onset of blood lactate accumulation (OBLA), running economy (RE), and maximal oxygen uptake were determined using the incremental treadmill test. The RE was represented by a VO2 value measured at 240 m.min-1 of a standard treadmill velocity. A stepwise multiple regression analysis (SAS stepwise procedure) combined the best features of forward inclusion and backward elimination to determine the most important factors in predicting the performance of running these distances as dependent variables. The stepwise procedure showed that the blood lactate variables such as LT and/or OBLA are highly correlated with, and contributed to predicting performance running 800 m-3000 m, whereas the anaerobic component was related only to running 800 m. In conclusion, blood lactate variables account for a large part of the variation in distance running performance in female as in male runners. The component of the anaerobic system which can be measured by the WAnT was shown to contribute to performance in running 800 m, but not in longer distances.

Adult↗
PubMed1990

HLA-DQ-specific autoreactive T cell clone with helper and cytotoxic functions.

To clarify the existence and the possible function of DQ-specific autoreactive T cells, we established a novel autoreactive T cell clone (28B8) responding to self-DQ molecules from an unimmunized normal subject. Blocking studies with monoclonal antibodies (mAbs) to HLA class II antigens and alloreactive response of the clone revealed that the clone recognized DQ molecules defined by a DR1-DQw5 haplotype. Clone 28B8 markedly induced autologous B cells to produce immunoglobulins, and was also cytotoxic against autologous lymphocytes, as well as against allogeneic lymphocytes with a DR1-DQw5 haplotype. These findings indicate that DQ antigens are involved in autoreactivity and stimulate autologous T cells that may have potent immunoregulatory functions.

Antibodies, Monoclonal↗
PubMed1990

Tumor uptake of [48V]vanadyl-chlorine e6Na as a tumor-imaging agent in tumor-bearing mice.

[48V]Vanadyl-chlorine e6Na (48V-Chl) which was synthesized by insertion of 48V (positron emitter) into chlorine e6Na (Chl), a chlorophyll derivative having a similar structure to pheophorbide-a (Pheo), localized rapidly in experimental mammary carcinoma. The tumor-to-organ ratios of 48V-Chl were higher than those of 48V-labeled Pheo (48V-Pheo), and 48V-Chl showed a clear tumor image with low accumulation in liver, depending on the biodistribution of metal-free Chl having an affinity with tumor. 48V-Chl seems to be more suitable than 48V-Pheo as a tumor-imaging agent for photodynamic therapy of tumors.

Animals↗
PubMed1990

Disruption of microtubules as an early sign of irreversible ischemic injury. Immunohistochemical study of in situ canine hearts.

Structural disruption of the cytoskeleton may be involved in irreversible ischemic injury. In the present study, ischemic changes in microtubules during various periods of myocardial ischemia were studied with an immunohistochemical technique in open-chest dogs. In intact myocardium, microtubules were stained as a filamentous network throughout cytoplasm and a circular network around the nucleus, which disappeared with colchicine treatment. In brief ischemia of less than 15 minutes, microtubule patterns were unaltered. After 20 minutes, however, characteristic microtubule stains were partly lost in patchy lesions. As an increase in ischemic period, lesions of loss of microtubule stains were increased in number and size. After 120 minutes of reperfusion following 60 minutes of ischemia, the lesions with intact actin filaments but with disrupted microtubules were replaced by the severely injured cells in which the regular myofibrillar registrations were distinctly disrupted. After 24 hours of reperfusion following 40 minutes of occlusion of the left circumflex artery, the percent area of disrupted microtubules at 40 minutes of ischemia was replaced by that of irreversibly injured lesions in the posterior papillary muscle. These results indicate that disruption of microtubules during ischemia heralds irreversible ischemic injury. However, in in vitro study, the myocardium incubated in hypoxic solution for 60-120 minutes demonstrated earlier disruption of the microtubules than the vinculin. Electron microscopic study also showed minimal irreversible changes in the lesions with disrupted microtubules. Thus, taken together, we conclude that microtubules that support the structural integration of myofibrils and other organelles are disrupted in severe myocardial ischemia before the irreversible injury, promoting the irreversible change after reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

The role of Na+/H+ exchange in norepinephrine-induced protein synthesis in neonatal cultured rat cardiomyocytes.

It is reported that Na+ influx contributes to stretch-induced cardiac hypertrophy. Na+ influx may also be involved in cardiac hypertrophy induced by catecholamine. In the present study, to test whether Na+/H+ exchange plays an important role in norepinephrine-induced cardiac hypertrophy, the effect of Na+/H+ exchange inhibitor, amiloride on protein synthesis was studied in cultured neonatal rat cardiomyocytes in serum free medium. [3H]Phenylalanine uptake was determined 24 and 48 hours after administration of norepinephrine with and without amiloride. In the control, norepinephrine increased [3H]phenylalanine uptake in a dose dependent manner (10(-5)-10(-7) M). Prazosin (10(-7) M) and amiloride (10(-5)-10(-4) M) significantly attenuated the norepinephrine mediated protein synthesis. These results indicate that alpha 1-adrenergic stimulation enhances the protein synthesis through activation of Na+/H+ exchange. Therefore, Na+ influx and/or PH increase may play a key role in cardiac hypertrophy.

Amiloride↗
PubMed1990

[Stress analysis of bridge abutment teeth with cemented dowels].

Stress analysis of bridge abutment teeth having cemented dowels was conducted using a two-dimensional finite element method. The results obtained are as follows: 1. In fixed-fixed bridges, compressive stress was found concentrated within the dowel, on the mesial side of the dowel apex, and in the distocervical part of the crown. 2. In cantilever bridges, tensile stress was found concentrated in the disto-occlusal and mesiocervical parts of the crown, and along the mesial sides of the root and the dowel. Compressive stress was concentrated in the distocervical part of the crown, along the distal sides of the root and dowel, and on the mesial side of the dowel apex. 3. In comparison with fixed-fixed bridges, stresses were significantly greater in cantilever bridges in the abutment teeth, the dowel, and crown margins. 4. In both fixed and cantilever bridges, stresses increased in relation to the length of the span. The rate of increase was less, however, in fixed-fixed than cantilever bridges.

Dental Abutments↗
PubMed1990

Effect of a histidine-excess diet on a tetrahydrofolylpolyglutamate pattern in rat liver.

The effect of a histidine-excess diet on the hepatic folylpolyglutamate pattern in rat was studied. Rats were fed ad libitum 9.7% casein basal diets with 0.6% methionine (controls) or the basal diets with 3.5% histidine. The average daily weight gain and the food intake in histidine-supplemented rats (His-rats) did not significantly differ from controls. The liver weight in His-rats, however, was 50% higher than controls. Hepatic methyltetrahydropteroylpentaglutamate (CH3-H4PteGlu5), and tetrahydropteroylmonoglutamate concentrations in His-rats was 5.7- and 2-fold higher than controls, respectively. The tetrahydropteroylpentaglutamate (H4PteGlu5) concentration in the His-rats was 74% lower than controls. Considering the homeostasis of folate cofactors in tissues, these results suggest that the hepatic regeneration systems for H4PteGlu5 in His-rats might be repressed and an apparent methylfolate trap might be attained rather on a pteroylpentaglutamate level than a monoglutamate level, and that the activity for catabolizing the excess histidine might exceed the regenerating activity for folate cofactors.

Animals↗
PubMed1990

[Tuberculosis sequelae: pathological findings].

Pathological examination of tuberculosis sequelae was carried out to clarify the nature and pathogenesis of sequela. Twenty-one cases were chosen from autopsied cases in the past 15 years; male 20, female 1, and age ranged from 43 to 78 and mean age was 59 years. Sequela cases were divided into two subgroups; low lung function subgroup (LLFS) and non-low lung function subgroup (NLLFS). LLFS had 10 cases and mean age was 55 years. Ten cases of bilateral fibrotic cavities, 10 cases of bilateral upper lobe atelectatic indurations, 4 cases of pneumonectomy, 4 cases of thoracoplasty, and others were basic lesions of sequela. Lobar atelectatic induration was formed of organized destructive pneumonia and suspected to follow the tuberculous granulomatous pneumonia. Seven cases of localized emphysema, 11 cases of bullae were seen as the secondary change. Mean heart weight was 335 gr and left ventricle + septum: right ventricle (LV+S: RV) ratio decreased to 1.24 among LLFS and mean heart weight 273 gr and Lv+S: RV ratio was 2.35 in NLLFS. Remaining of cavities were observed in 15 cases and Aspergillus infection was seen in 11 cases (7 cases formed fungus ball, 4 cases showed semi-invasive growth and 2 out of 4 showed necrotizing pneumonia and formed direct cause of the death). Terminal infection was seen in 10 cases. According to our data, chronic lung failure with cor pulmonale, secondary fungus infection in the remained cavity, and terminal infectious pneumonia were serious consequence of tuberculosis sequela.

Adult↗
PubMed1990

[Ferruginous bodies in the lungs of the general population during a 45-year period and mineralogical examination].

In order to determine the level of asbestos pollution in the lungs of members of the general population in and around Tokyo, the incidence of ferruginous bodies in autopsied or resected lungs during 5 periods over the 45 years from 1937 to 1981 was studied by a light microscopy. Core fibres, after removal of their ferruginous coatings with oxalic acid, and uncoated fibres were analyzed using a scanning electron microscope equipped with a Kevex energy-dispersive X-ray spectrometer. The incidence of ferruginous bodies in 5 g (wet) of digested lung tissue was shown to be 10% in period I (1937-1941), 18% in period II (1947-1951), 70% in period III (1958-1963), 74.4% in period IV (1970-1973) and 81.0% in period V (1980-1981). The major types of core fibres of ferruginous bodies were found to be asbestos, including amosite, crocidolite, chrysotile and the tremolite-actiolite series, but a small number of fibers of materials other than asbestos were also detected. In contrast, a large number of short fibers less than 5 microns in length in 1 g of wet lung tissue were classified as belonging to Mg + Si fibers (the ratio of Mg to Si components being 30% or over) and presumed to be chrysotile. Thus an annual increase in asbestos deposition in lungs of people living in and around Tokyo has been demonstrated and fine chrysotile fibers less than 5 microns in length seem to be the main type of deposited fibers.

Asbestos↗
PubMed1989

Introduction and expression of the human insulin gene in adult rat liver.

Liposomes associated with gangliosides and loaded with the human insulin gene were incubated with HVJ (Sendai virus) and red blood cell membranes containing non-histone chromosomal protein, high mobility group 1 (HMG-1), or bovine serum albumin (BSA) to form vesicle complexes. These vesicle complexes were then injected into the portal vein of adult rats. The insulin gene co-introduced with HMG-1 was transported into the nuclei of liver cells much more efficiently than the gene co-introduced with BSA. Moreover, the amount of transcript of the insulin gene co-introduced with HMG-1 was more than 10 times greater than that of the gene co-introduced with BSA. Similar amounts of DNA and RNA of human insulin were found in the liver within 7 days after injection of the gene, and then the amounts of both decreased rapidly. The level of human insulin in rat serum gradually increased to a maximum (20-30 microunits/ml) after 7 or 8 days and then decreased rapidly.

Animals↗
PubMed1989

Increased expression of DNA cointroduced with nuclear protein in adult rat liver.

DNA and nuclear proteins were transferred into cells simultaneously at more than 95% efficiency by means of vesicle complexes. The DNA was rapidly transported into the nuclei of cultured cells, and its expression reached a maximum within 6 to 8 hours after its introduction. Moreover, when the plasmid DNA and nuclear protein were cointroduced into nondividing cells in rat liver by injection into the portal veins of adult rats, the plasmid DNA was carried into liver cell nuclei efficiently by nuclear protein. The expression of the DNA in adult rat liver, on introduction of the DNA with nuclear protein, was more than five times as great as with nonnuclear protein.

Animals↗
PubMed1989

Immunohistochemical expression of epidermal growth factor receptor in salivary gland tumours.

Immunohistochemical localization of epidermal growth factor receptor (EGFR) in normal salivary glands and tumours (108 cases) was studied using a monoclonal antibody. In the normal salivary glands, EGFR was occasionally detected in ductal segments of intercalated, striated, and excretory ducts, but not in acinar cells. The frequency of positive EGFR staining in salivary gland tumours was not high: pleomorphic adenoma, 33.8%; mucoepidermoid tumour, 25.0%; adenolymphoma, 44.4%; and sialoadenocarcinoma, 66.6%. Pleomorphic adenomas showed positive staining for EGFR on the luminal side of luminal cells and in squamous metaplastic cells of tumour tissue. Some modified myoepithelial cells were also reactive whereas outer spindle tumour cells were unstained. Adenolymphomas regularly exhibited positive EGFR staining in the cell membrane; mucoepidermoid carcinoma displayed positive staining in cell membranes in epidermoid tumour cells and cytoplasmic staining in mucous-secreting tumour cells. Sialocarcinomas revealed cell membrane staining and whole cytoplasmic staining for EGFR. The immunohistochemical localization of EGFR could be classified into two types, one the cell membrane-positive type found in epithelial tumour cells, and the second the cytoplasmic positive type seen in normal ductal cells, the luminal tumour cells of pleomorphic adenomas and mucous-secreting tumour cells.

ErbB Receptors↗
PubMed1989

Heterogeneity in terms of interleukin 4-dependent regulation of Fc epsilon...receptor/CD23 expression on chronic B-lymphocytic leukemia cells.

To discriminate the stages of maturation arrest of leukemic B cells, we have investigated the cell surface expression of Fc epsilon RII (H107 antigen) on leukemic B cells from 6 patients with chronic type B-lymphocytic leukemia (B-CLL) by a double staining method combined with cytofluorometry, and their production of soluble Fc epsilon RII by an ELISA technique. Fc epsilon RII was expressed on mu+/delta- cells of case 5 as well as on mu+/delta+ cells of cases 1, 2 and 4, but not on mu+/delta+ cells in cases 3 and 6. The cultivation of leukemic cells with IL-4 not only increased the percentage of Fc epsilon RII+ cells but also enhanced the production of soluble Fc epsilon RII+ in most cases. However, IL-4 had no effects on mu+/delta-/Fc epsilon RII+ cells of case 5, which appeared to correspond to a rather late stage of normal B cell differentiation. Moreover, while leukemic B cells from case 1 spontaneously produced large amounts of soluble Fc epsilon R, the release seemed to be inhibited by an addition of IL-4. From our observations, it is speculated that IgM+/IgD+/Fc epsilon RII- leukemic B cells express surface membrane Fc epsilon RII and produce soluble Fc epsilon RII following stimulation with IL-4, and that IgM+/IgD-/Fc epsilon RII+ B-CLL cells may exist at some late stage of B cell differentiation.

Aged↗
PubMed1989

Localizing efficiency of [48V]vanadyl-pheophorbide in tumor as a new tumor imaging agent.

[48V]vanadyl-pheophorbide (48V-Pheo) was synthesized by insertion of 48V into pheophorbide (Pheo), a decomposition product from chlorophyll. At 24 h after injection, 48V-Pheo showed a clearer image of an FM3A tumor than inorganic 48V. This agent also accumulated in MH 134 and S 180 tumors as well as in FM3A tumors. The imaging efficiency was dependent on the affinity of Pheo for tumors. 48V-Pheo seems to be suitable as a tumor imaging agent in conjunction with photodynamic therapy.

Animals↗