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Biomedical subjects

T Oka

Publications and source records attributed to T Oka.

At least 793 records · Page 44Linked to original sources
PubMed1991

Prolongation of renal allograft survival in the rat treated with amniotic fluid.

To assess the role of amniotic fluid (AMF) in the maintenance of pregnancy, immunosuppressive effects of AMF were studied in vivo, and the mechanisms of suppressor activity were analyzed immunologically in vitro in the rat. Female Lewis (LEW, RT-1l) rats mated with Brown-Norway (BN, RT-1n) rats for 14 days were sacrificed and cell-free AMF was obtained. AMF was diafiltered with PBS (PH 7.2) and reconstituted to 2 OD units measured at 280 nm. Untreated LEW hosts rejected BN renal grafts at 7.8 +/- 0.2 days (n = 10). Five days of intravenous inoculation of AMF into LEW hosts remarkably enhanced BN graft survivals (MST = 20.3 +/- 4.4 days, n = 12) compared with controls (P less than 0.01), and slightly prolonged third-party DA (RT-1a) graft survivals (MST = 9.4 +/- 0.8 days, n = 7) compared with control LEW hosts engrafted with a DA kidney (MST = 7.6 +/- 0.2 days, n = 6). Five days of intravenous inoculation of pregnant sera into LEW hosts had no effect on BN graft survival. The AMF suppressed the proliferative response of LEW lymphocytes against not only irradiated BN stimulator cells but also irradiated third-party DA stimulators. The AMF also suppressed allokiller T cell generation of normal LEW lymphocytes against BN cells by 70.1% and 51.3%, and against DA cells by 64.9% and 38.9% at concentrations of 25% and 12.5%, respectively (P less than 0.01). To dissect the immunosuppressive activity of AMF, the effect of AMF on cytokine production and interleukin 2 (IL-2) receptor expression of concanavalin A-stimulated lymphocytes were investigated. AMF suppressed interferon and IL-2 production. Interestingly, however, AMF did not suppress interleukin 3 (IL-3) and interleukin 6 (IL-6) production, as well as IL-2 receptor expression. These results demonstrated that rat AMF displayed a strong immunosuppression in vivo as well as in vitro, and that AMF might play an important role in the maintenance of pregnancy.

Amniotic Fluid↗
PubMed1991

The effect of PGE1 and temperature on lung function following preservation.

We studied the effect of a vasodilator (prostaglandin E1) as well as flush (F) and storage (S) temperatures (4 degrees C or 10 degrees C) on lung preservation in an isolated rabbit lung perfusion model. Low-potassium dextran (LPD) or Euro-Collins (E-C) solution was used as flush solution. Six groups of six animals were studied: group 1 (LPD, 4 degrees C F-S), group 2 (LPD with PGE1, 4 degrees C F-S), group 3 (E-C with PGE1, 4 degrees C F-S), group 4 (LPD, 10 degrees C F-S), group 5 (LPD with PGE1, 10 degrees C F-S), group 6 (E-C with PGE1, 10 degrees C F-S). After 18-hr preservation, left lungs alone were ventilated, and reperfused with fresh venous blood. PaO2, PaCO2, pulmonary artery pressure (PAP), tracheal pressure (Pt) during reperfusion, and wet/dry weight (W/D) ratios were measured. PaO2 after LPD with or without PGE1 was significantly higher than after E-C with PGE1 at 4 degrees C (95.8 +/- 11.5 mmHg in group 1 or 102.7 +/- 8.6 in group 2 vs. 41.8 +/- 10.5 in group 3, P less than 0.01) and at 10 degrees C (119.3 +/- 2.3 in group 4 or 131.1 +/- 6.2 in group 5 vs. 54.6 +/- 5.2 in group 6, P less than 0.01). PaCO2, PAP, Pt, and W/D ratios in the LPD groups were lower than in the E-C groups. LPD/PGE1 and LPD alone produced similar pulmonary preservation. PaO2 of lungs flushed with LPD and preserved at 10 degrees C was higher than that of lungs stored at 4 degrees C. We conclude that LPD solution is superior to E-C solution in this ex vivo rabbit lung preservation model, even when PGE1 is used. A moderate dose of PGE1 did not improve the performance of LPD as a flush solution. Pulmonary preservation with LPD at 10 degrees C is superior to preservation at 4 degrees C.

Alprostadil↗
PubMed1991

Low-potassium UW solution for lung preservation. Comparison with regular UW, LPD, and Euro-Collins solutions.

University of Wisconsin solution has been used successfully in clinical kidney and liver preservation. The object of this study was to determine if low-potassium UW (LPUW) solution could be applied to pulmonary preservation. Rabbit lungs were stored after hypothermic pulmonary artery (PA) flush with four different solutions (group 1: low-potassium dextran (LPD) solution, group 2: high-potassium UW (HPUW) solution, group 3: LPUW solution, group 4: modified Euro-Collins (E-C) solution). The lungs were preserved at 10 degrees C for 30 hr and evaluated in an ex vivo ventilation/perfusion apparatus using fresh pooled venous rabbit blood. Mean PA flush pressures (MFP) during harvesting were significantly lower in groups 1 and 3 (8.1 +/- 1.0 mmHg and 7.3 +/- 0.6 mmHg, respectively; mean +/- SEM) than in groups 2 and 4 (15.5 +/- 1.7 mmHg and 12.3 +/- 0.9 mmHg, respectively). Lungs in groups 1 and 3 showed significantly higher PaO2 (103.5 +/- 8.0 mmHg and 89.3 +/- 7.2 mmHg) than groups 2 and 4 (48.3 +/- 7.7 mmHg, 66.7 +/- 4.7 mmHg). Groups 1 and 3 showed significantly lower wet/dry weight (W/D) ratios after reperfusion (6.21 +/- 0.15 and 6.39 +/- 0.23) than groups 2 and 4 (7.70 +/- 0.57 and 7.13 +/- 0.21, respectively). There were no significant differences in MFP, PaO2, PaCO2, mean pulmonary artery pressure, or W/D ratio between groups 1 and 3. These results suggest that LPUW solution may be as beneficial as LPD solution for pulmonary arterial flush and lung preservation.

Adenosine↗
PubMed1991

Purification and partial characterization of a soluble hemagglutinin from Yersinia pseudotuberculosis.

A soluble hemagglutinin (HA) produced by Yersinia pseudotuberculosis strain Inoue, serotype 5b, was purified by ammonium sulfate precipitation, gel filtration on Sepharose CL-6B and high performance liquid chromatography on a DEAE-5PW anion-exchange column. The purified HA was a 14.5 kDa protein with an isoelectric point of 4.5. Amino acid analysis indicated that the HA consisted of 133 residues, corresponding to the molecular weight of 14,100. The amino acid sequence of N-terminal 38 amino acid residues showed no homology with that of several fimbrial proteins from Escherichia coli.

Amino Acid Sequence↗
PubMed1991

S layer protein of Clostridium tetani: purification and properties.

S layer protein of Clostridium tetani strain AO 174, a nontoxigenic derivative of strain Harvard A 47, was prepared from the cell walls by 4 M urea extraction and purified by DEAE-Sepharose CL-6B chromatography followed by a combination of anion-exchange chromatography and reverse-phase chromatography using an HPLC system. The molecular weight of the S layer protein was estimated to be 140 kilodaltons (kDa) by SDS-PAGE. The amino acid composition of the 140 kDa protein was very similar to those of S layer proteins from the other bacterial species: it was rich in acidic amino acid and lacked cysteine. Also, the protein was unique in its extremely low content of proline (0.02 to 0.03 mol%). Multiple isoelectric forms ranging from pH 4.0 to 4.5 were observed in the purified preparation. Immunodiffusion analysis showed that the 140 kDa protein was a common antigen to the three strains of C. tetani tested.

Amino Acids↗
PubMed1991

Familial aggregation of cancer from proband cases with childhood adrenal cortical carcinoma.

Family pedigree of Li-Fraumeni syndrome was investigated from probands with childhood adrenocortical carcinoma in Japan. From 47 probands, 7 families had 3 or more cancer cases at ages less than 45 years within the first generation; one satisfied Li's original criteria, two were acceptable because of multiple primary cancer in the probands, and others showed an aggregation of cancers with onsets at early ages, though no sarcoma of mesenchymal origin was found. A significantly higher occurrence of cancer in the mothers of the probands, especially of the breast, was consistent with reports from the USA, and liver cancer, osteosarcoma and lung cancer among family members under the age of 45 also showed a higher frequency than in the general population. Similarities and differences between Japanese and Caucasian cases are discussed.

Adolescent↗
PubMed1991

Interleukin-2 receptor gene expression in kidney transplant recipients treated with cyclosporin A.

We examined the effects of cyclosporin A (CsA) administered in vivo on the capacity of peripheral blood mononuclear cells (PBMC) from kidney transplant recipients to express IL-2 receptor (IL-2R) gene at the level of mRNA after mitogen stimulation in vitro. There were no differences in the percentage of IL-2R+ cells among the groups of normal individuals, azathioprine-prednisolone treated, and CsA-prednisolone-treated recipients, using FITC-labelled monoclonal anti-IL-2R antibody (anti-alpha chain): 40.3 +/- 10.1% and 62.8 +/- 11.1% of normal PBMC (n = 18), 37.0 +/- 9.3% and 61.7 +/- 5.8% of PBMC from azathioprine-prednisolone-treated recipients (n = 20), and 37.7 +/- 9.6% and 60.7 +/- 12.7% of PBMC from CsA-prednisolone-treated recipients (n = 20) expressed IL-2R after 24 h and 48 h of phytohaemagglutinin stimulation, respectively. However, in a study of Northern blotting using cDNA for IL-2R (anti-alpha chain specific), both the 3500 and 1400 bp families of IL-2R mRNA were remarkably decreased in PBMC from CsA-prednisolone-treated recipients compared with azathioprine-prednisolone-treated recipients and normal individuals. These studies demonstrated that CsA could inhibit IL-2R gene expression at the level of mRNA at physiological concentration.

Adult↗
PubMed1991

Mixed invasive aspergillosis and candidiasis in a fatal case of leukemia.

A fatal case of leukemia complicated by mixed invasive aspergillosis and candidiasis is presented. Mixed fungal infections may occur in any immunocompromised patients. We should be careful to look for different morphologies of fungi in diagnostic examinations of lesions in these patients.

Adolescent↗
PubMed1991

Effect of salivary epidermal growth factor on wound healing of tongue in mice.

The role of salivary epidermal growth factor (EGF) in wound healing of the tongue was studied in mice. Sialoadenectomy (removal of the submandibular glands, which are the major source of salivary EGF) or sham operation was performed 2 wk before infliction of wound on the tongue. Salivary EGF levels were 1.98 +/- 0.47 and 0.20 +/- 0.04 (SE) microgram/ml in sham-operated male and female mice, respectively, whereas sialoadenectomy reduced salivary EGF to undetectable levels in both male and female mice. A circular superficial wound measuring approximately 2 mm in diameter was made in the middle of the tongue by mechanically ablating only the epithelial layer. The rate of wound healing was monitored by a stereomicroscopy. Sialoadenectomized male mice showed a significant delay in wound healing compared with sham-operated controls. Treatment of sialoadenectomized male mice with EGF (1 microgram/ml in drinking water) restored the rate of wound healing to normal levels. Transforming growth factor (1 microgram/ml) was as effective as EGF in the promotion of wound healing, whereas nerve growth factor (1 microgram/ml) was ineffective. Essentially the same results were obtained in female mice. In addition, two classes of EGF binding sites with high and low affinity were demonstrated in the epithelium of the tongue obtained from male and female mice. The maximum binding sites and dissociation constants of the EGF receptors were the same between males and females and were not affected by sialoadenectomy. These results suggest that salivary EGF is involved in the promotion of wound healing of the tongue in both male and female mice.

Animals↗
PubMed1991

Single cilium in human leukemic cells heterotransplanted into hamsters.

Single cilium formation was studied in two human hematopoietic cell lines, KCL-22 and MT-2, KCL-22, established from a patient with chronic myelogenous leukemia in blastic crisis, and MT-2, a human cord T cell line carrying human T-lymphotropic virus type I, were transplanted into hamsters. Ciliogenesis was observed in both cell lines, only after transplantation into hamsters.

Animals↗
PubMed1991

Pretranslational enhancement of epidermal growth factor receptor by direct effect of testosterone in mouse liver.

The effects of testosterone on the levels of epidermal growth factor receptor (EGFR) in mouse liver were studied. Orchiectomy resulted in 39% and 41% reductions in the levels of EGFR mRNA and EGF binding, respectively, within 2 weeks. Treatment of orchiectomized mice with a sc injection of testosterone propionate (TP; 100 micrograms/mouse.day) for 1 week restored these values to normal male levels. The hepatic levels of EGFR mRNA and EGF binding in females were 37% and 36% of those in males, respectively, and were not affected by ovariectomy, whereas treatment of females with TP (100 micrograms/mouse.day) increased EGFR to normal male levels within 1 week. On the other hand, neither orchiectomy nor androgen treatment affected levels of mRNAs for EGFR in the kidney or mRNAs for the structural protein beta-actin in the liver. To examine whether testosterone directly increased EGFR levels in the liver, TP (1.0 mg) pellets were implanted into the spleen of orchiectomized mice, so that testosterone released from the pellets reached the liver through the portal vein but did not enter the systemic circulation due to rapid clearance by the liver. The heptic levels of EGFR mRNA and EGF binding in orchiectomized mice were restored to normal male levels by intrasplenic implantation of TP (1.0 mg) pellets. This treatment also increased the hepatic levels of EGFR mRNA and EGF binding in female mice by 61% and 68%, respectively. In addition, sialoadenectomy, which reduced plasma EGF, as well as EGF antiserum treatment did not affect the androgen-dependent increase in EGFR levels in the liver, suggesting that endogenous EGF is not involved in the androgenic regulation of hepatic EGFR levels. These results suggest that hepatic EGFR levels are at least in part regulated at a pretranslational level by direct effects of androgens on the liver.

Animals↗
PubMed1991

Influence of epidermal growth factor on liver regeneration after partial hepatectomy in mice.

The role of epidermal growth factor (EGF) in liver regeneration was studied in mice after partial hepatectomy. Two weeks before partial hepatectomy, mice were sham-operated (control) or sialoadenectomized (removal of submandibular glands) to reduce plasma EGF levels. Sialoadenectomized mice showed low plasma EGF levels (29.7 +/- 6.6 pmol/l; mean +/- S.E.M.) compared with controls (66.0 +/- 8.3 pmol/l). After partial hepatectomy, sialoadenectomized mice were treated with or without a daily s.c. injection of 5 micrograms EGF and the rate of DNA synthesis in the regenerating liver was monitored by [125I]iododeoxyuridine uptake. Control mice showed a sharp peak of DNA synthesis at 48 h after partial hepatectomy while sialoadenectomized mice showed a delayed and broad peak at 84 h. Treatment of sialoadenectomized mice with EGF (5 micrograms/mouse per day) completely restored the pattern of DNA synthesis so that a sharp peak appeared at 48 h. The total liver DNA content of the control mice (79.1 +/- 2.5% of the preoperative level; mean +/- S.E.M.) was significantly (P less than 0.01) higher than that of the sialoadenectomized mice (65.2 +/- 3.0%) 3 days after partial hepatectomy, but this difference disappeared on day 7 when liver regeneration was almost completed in both groups. Treatment of sialoadenectomized mice with EGF increased total liver DNA content (78.2 +/- 2.9%) to that of control mice on day 3 after partial hepatectomy. In addition, normal mice showed a rapid increase in plasma EGF levels at 1-8 h after partial hepatectomy, whereas sialoadenectomized mice showed low plasma EGF levels throughout the course of the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Control of growth and differentiation of the mammary gland by growth factors.

Mammary gland development is a complex process regulated by various steroid and polypeptide hormones. Although the systemic importance of hormones, such as estrogen, progesterone, prolactin, and growth hormone, in the growth of the mammary gland has been well documented, these hormones are virtually incapable of stimulating mammary cell growth in vitro. Thus, the growth stimuli for mammary cells requires clarification. In recent years, a number of growth factors have been discovered; this has prompted interest in examining possible involvement of these biologically active agents in the process of mammary gland development. Results presented herein indicate that several growth factors including epidermal growth factor, transforming growth factor alpha and beta, basic fibroblast growth factor, insulin-like growth factor-I, and mesenchyme-derived growth factor participate in the regulation of mammary cell growth and differentiation.

Animals↗
PubMed1991

Method for in situ evaluation of superoxide production by pulmonary macrophages in the rat.

In order to investigate superoxide production by pulmonary macrophages in the rat, a route was created by ligating both the inferior and superior venae cavae and resecting the aorta after cannulation through the inferior vena cava into the right atrium of the heart. Lung perfusion was performed via this route with nitro blue tetrazolium. Although there was no formazan deposition throughout the lung, it became detectable in both alveolar and interstitial macrophages when phorbol myristate acetate was added to the perfusate. This deposition was markedly enhanced by previous injection of Corynebacterium parvum. The deposition disappeared after further addition of Cu(Lys)2, a scavenger of superoxide anions. This procedure may be useful for estimating in situ the ability of pulmonary macrophages to produce superoxide in the rat.

Animals↗
PubMed1991

[An analysis of 70 patients with bilobectomy for bronchogenic carcinoma].

From 1955 to April 1989, 70 patients underwent bilobectomy for the treatment of primary lung carcinoma. Thirteen patients (18.6%) underwent right upper and middle lobectomy (UML), while 57 patients (81.4%) underwent right middle and lower lobectomy (MML). Indications for bilobectomy were cancer invasion into intermediate bronchus (34%), tumor extending to neighbouring lobe across a fissure (29%), interlobar lymph nodes metastasis with or without invasion to intermediate bronchus (24%), vascular invasion (5%), and others (7%). Squamous cell carcinoma was present in 31 patients, adenocarcinoma in 28, large cell carcinoma in 5, small cell carcinoma in 4 and others in 2. About 60 percent of the patients had Stage III or IV diseases. Postoperative complications occurred in 27 patients (38.6%) and 3 died within 30 days after operation (operative mortality rate. 4.3%). Pneumonia, empyema, atelectasis and arrhythmia were prominent postoperative complications. There were no statistically different postoperative complication rates between those with UML and those of MLL. Five-year survival rate of the patients with bilobectomy for lung cancer was 25.7%, which was between those with single lobectomy (36.9%) and those with pneumonectomy (5.6%). However, there was no statistical difference in 5-year survival rate among operative procedures in each stage.

Adenocarcinoma↗
PubMed1991

[The examination of DNA strand breaks induced by peplomycin-using non-radioactive in situ nick translation method].

In situ nick translation (ISNT) is a method to detect DNA single strand break (nick) at each cellular level. In this study, peplomycin (PEP)-induced DNA strand breaks and its repair were examined using non-radioactive ISNT method. Human fibroblasts were cultured with various concentrations of PEP for different durations, and then DNA strand breaks were evaluated by ISNT method. The signal intensity of DNA strand breaks of the PEP-treated fibroblasts was increased in a dose dependent manner. At the fixed concentration of PEP, it reached to a maximum level after 10 min. of culture and remained unchanged for at least 24 hours. In addition, DNA strand breaks induced by PEP was rapidly repaired in 10 min. after washing. Thus, the non-radioactive ISNT is thought to be a quick, sensitive and specific method not only to detect DNA strand breaks but also to observe its repair.

Bleomycin↗