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Biomedical subjects

A Manabe

Publications and source records attributed to A Manabe.

At least 109 records · Page 6Linked to original sources
PubMed1993

Effect of delayed light curing of a resin composite on marginal integrity in cylindrical dentine cavities.

The effect of delayed light curing of resin composite on marginal adaptation has been examined by measuring the wall-to-wall polymerization contraction gap when using a commercial resin composite together with experimental dentine bonding systems to restore cylindrical preparations in dentine. Morphological changes in dentine during dentine bonding procedures were observed using a scanning electron microscope. In a previous report, the contraction gap width for a resin composite increased when irradiation of the resin system was delayed, despite the use of a dentine bonding system considered to be 'contraction' gap free. Such deterioration in marginal adaptation was minimized by use of an experimental dentine primer, 40% erythritol methacrylate aqueous solution (EM), followed by the use of a commercial dual- or autocured dentine bonding agent. Under scanning electron microscopy, the dentine surface microstructure became unclear after EM priming, and a polymer film was detected after polymerization of the dual-cured dentine bonding agent. The hydrogelled primer and the formation of a polymer network on the dentine surface may prevent the flow of fluid from the pulp through the dentine tubules, and maintain marginal integrity if there is delay in light curing of light-activated resin composite systems.

Analysis of Variance↗
PubMed1993

Stroma-supported immunocytometric assay (SIA): a novel method for testing the sensitivity of acute lymphoblastic leukemia cells to cytotoxic drugs.

The accuracy of drug-sensitivity assays for neoplastic cells depends on the ability to sustain cell survival in vitro, but cells in most cases of acute lymphoblastic leukemia (ALL) rapidly die by apoptosis in culture. We recently reported that allogeneic bone marrow stromal layers support long-term culture of ALL cells. We now describe the standardization of a novel drug-sensitivity assay for ALL lymphoblasts maintained on stromal layers, in which the viability of treated and untreated cells is compared using flow cytometry. Cultures were performed in U-bottomed 96-well plates: 2 x 10(4) stromal cells per well produced rapidly confluent layers which supported the survival of ALL blasts. In four ALL cases studied, 68.8-106% (median 94.8%) of the lymphoblasts originally seeded were recovered after 7 days of culture, in contrast to < 5% recovered in the absence of stroma. Sensitivity to five antileukemic drugs was tested at the indicated concentrations: vincristine (0.001-1 microgram/ml); dexamethasone (0.001-100 microM); 6-thioguanine (0.078-20 micrograms/ml); teniposide (0.001-10 microM); cytosine arabinoside (0.039-10 microM). After 4 days of culture, cells were labeled with CD19 monoclonal antibody and analyzed by flow cytometry. The concentration of each antileukemic agent producing 50% cytotoxicity (LC50) was determined for each patient by fitting a sigmoid model to the drug concentrations versus percentage viability data. Clinically relevant drug concentrations produced cytotoxic effects, and ALL blast sensitivity varied considerably among patients. We conclude that this is an informative method of systematically evaluating drug sensitivity in ALL patients.

Adolescent↗
PubMed1993

Use of stroma-supported cultures of leukemic cells to assess antileukemic drugs. I. Cytotoxicity of interferon alpha in acute lymphoblastic leukemia.

Leukemic cells from most cases of acute lymphoblastic leukemia (ALL) rapidly die by apoptosis in vitro, unless they are cultured onto bone marrow-derived stromal layers. We have recently established a stroma-supported tissue culture technique that allows long-term culture of leukemic lymphoblasts. In this study, we used this technique to examine interferon alpha (IFN alpha) cytotoxicity to ALL blasts. In 16 ALL cases tested (14 B-lineage ALL, 2 T-ALL), the number of cells recovered after 7 days of culture on stromal feeder layers was 60-178% (median, 108%) of those originally seeded. The percentage of lymphoblasts killed by 2000 U/ml IFN alpha 2b after 7 days of culture, ranged from < 1% to 91% (median, 56%). Cytotoxicity was (i) dose-dependent, (ii) eliminated by a neutralizing antibody to IFN alpha, and (iii) accompanied by tyrosine phosphorylation of a 135 kDa protein, which was detectable after 5 minutes of treatment. Numbers of residual normal lymphoid cells in the cultures remained low and conditioned medium prepared from IFN alpha-stimulated T, NK, and stromal cells was not cytotoxic to ALL blast cells. In contrast to results in freshly isolated ALL cells, six ALL cell lines tested were completely resistant to IFN alpha cytotoxicity. We conclude that IFN alpha is directly cytotoxic in most ALL cases but that the intensity of its effects varies widely among cases. The method used in this study may be applied to evaluate leukemic blast cell sensitivity to compounds with potential antileukemic activity, and to select patients to be entered in to clinical trials.

Adolescent↗
PubMed1992

Bone marrow-derived stromal cells prevent apoptotic cell death in B-lineage acute lymphoblastic leukemia.

Establishing requirements for the survival of human immature B cells in vitro has proved elusive. In this article, we report prolonged survival of B-lineage leukemic cells on 'feeder layers' of bone marrow (BM)-derived stromal cells in a serum-free environment. In 15 of 18 cases of B-lineage acute lymphoblastic leukemia (ALL), there was a greater than 50% decrease in the number of viable cells after 72 hours of culture in medium alone. Cell loss was preceded by molecular and cellular changes characteristic of programmed cell death, or apoptosis, and was not suppressed by adding interleukin-7 to the tissue culture medium. By contrast, the use of allogeneic BM stromal cells as feeder layers prevented apoptosis in 10 of 12 cases of ALL, leading to extended survival of the blast cells. This method was not successful when the allogeneic marrow cells were replaced with established cell lines. In six of eight cases in which the numbers of intact CD19+ lymphoblasts were counted by flow cytometry after 7 days of culture, the proportion of such cells recovered in the presence of BM stromal cells was 68.8% to 124.7% (median, 95.3%) of that originally seeded, as opposed to the 0.3% to 15.9% fraction (median, 0.7%) obtained in the absence of stromal cells. Survival requirements of the B-lineage lymphoblasts appeared to be heterogeneous, as cells from 3 of the 18 cases studied showed no signs of apoptosis in serum-free tissue culture medium that lacked BM stromal cells. The only cells not giving rise to viable cultures were from two hyperdiploid (greater than 50 chromosomes) cases with identical karyotypes. The serum-free assay described here can be used to compare the survival requirements of normal and leukemic B-cell progenitors as well as to identify the molecules involved in the interaction between BM stroma and immature B cells.

Adolescent↗
PubMed1992

New pelvic sonoangiography for detection of endometrial carcinoma: a preliminary report.

Pelvic sonoangiography (PSAG) using transvaginal color Doppler was done on 16 postmenopausal patients with abnormal uterine bleeding. Seven women had no endometrial carcinoma and nine had carcinoma. No flow was detected around and within the endometrium in noncancer patients. PSAG showed a feeder artery (blood flow with pulsation that runs into and clings to the tumor) in all patients with endometrial carcinoma, and intratumor blood flow (a mixture of pulsating and constant flow within the tumor) was evident in 7 of 9 patients with endometrial carcinoma. These findings were confirmed by conventional pelvic angiography. In the diagnostic evaluation of PSAG for endometrial carcinoma, both sensitivity and specificity were 100%. We conclude that PSAG with transvaginal color Doppler can be used to detect endometrial carcinoma in postmenopausal women with abnormal uterine bleeding and that this method might be applicable to selecting patients who really require diagnostic surgery for endometrial cancer.

Aged↗
PubMed1992

Ovarian tumors of low malignant potential: transvaginal Doppler ultrasound features.

Twenty-nine patients with ovarian tumors were studied with transvaginal Doppler ultrasound before surgery. After surgery, pathological examination revealed that 26 tumors were benign and 3 were of low malignant potential (LMP). B-mode sonography, computed tomography, and magnetic resonance imaging showed no positive findings for malignancy in these 3 cases of LMP. Serum levels of the CA-125, tissue polypeptide antigen, and carcinoembryonic antigen were also within the normal range. Blood flow velocity waveforms were evaluated by the calculation of the resistance index (RI). There was a significant difference between the RI value (0.818 +/- 0.223) in benign tumors and that (0.418 +/- 0.072) in LMP (P less than 0.01). When the 0.56 (mean of LMP tumor RI value + 2SD) was considered as the cutoff value of RI, the sensitivity was 100% and the specificity was 88.5%. Transvaginal Doppler ultrasound provides a useful diagnostic information for the differentiation of benign and LMP ovarian tumors before surgery.

Adult↗
PubMed1992

Ultrasonography and Doppler studies in twin-to-twin transfusion syndrome.

In 40 twin pregnancies, the evaluation of hemodynamics by ultrasound was performed during the period January 1986 through September 1991. The blood flow velocities' waveforms in the umbilical artery, umbilical vein and tricuspid valve, and the total cardiac dimension, were obtained by ultrasonography in conjunction with 3.5 MHz pulsed Doppler ultrasound. Six patients with twin pregnancies were identified as having twin-to-twin transfusion syndrome (TTS), on the basis of like-sex twins with monochorionic diamniotic placentation, vascular anastomosis in the placenta, and umbilical cord venous blood hemoglobin difference exceeding 5 g/dl at delivery. No distinctive findings for TTS were revealed by the measurement of umbilical artery blood flow velocity waveforms. However, cardiomegaly in 5 recipient fetuses and tricuspid regurgitation and biphasic umbilical vein waveforms in 3 recipient fetuses constituted characteristic features of TTS. Ultrasonography and a Doppler study might be beneficial in diagnosing TTS and evaluating the hemodynamics in a recipient fetus.

Blood Flow Velocity↗
PubMed1992

Fetal atrial measurements before and after delivery: correlation with plasma atrial natriuretic peptide.

Fetal and early neonatal atrial measurements correlating with plasma atrial natriuretic peptide were studied to evaluate the circulatory change before and after delivery in a longitudinal study of 10 normal fetuses from 1 week before until 5 days after delivery. Before delivery, right atrial area value was significantly larger than that of left atrial area; however, there were no significant differences between left and right atrial areas after delivery. Right atrial area value before delivery was significantly larger than those after delivery, whereas the left atrial area did not change before and after delivery. Combined atrial area value before delivery was also larger than those after delivery. Plasma atrial natriuretic peptide values did not change after delivery. These results suggest that the change from fetal to neonatal circulation mainly caused by the pulmonary circulation induces the change of right atrial size before and after delivery.

Atrial Natriuretic Factor↗
PubMed1992

Possibility of allergic reaction to dentin primer--application on the skin of guinea pigs.

We studied the allergic reaction of guinea pigs to glyceryl methacrylate (GM), hydroxyethyl methacrylate (HEMA) and meso-erythritol methacrylate (EM), which are used as dentin primers. On the 18th day of the application test, when macroscopic investigation revealed an inflammatory reaction, the methacrylic acid-treated group showed marked eschar formation in comparison with the control group. In each of the dentin primer groups, a slight degree of skin redness was noted, but there were no serious symptoms. On the 25th day, the applications were resumed macroscopic inspection on the 32nd day found eschar in the methacrylic acid group only. Therefore, this experiment with dentin primers suggests a delayed allergic reaction. Local irritability test showed a more severe reaction than the application test. In this test, all experimental dentin primers and methacrylic solution promptly showed inflammation, and the chemical compound, methacrylic acid was a factor in inflammation.

Animals↗
PubMed1992

Transvaginal Doppler ultrasound assessment of intratumoral hemodynamic change before and during hypertensive intra-arterial chemotherapy for uterine cancer.

OBJECTIVE: To evaluate blood flow in malignant uterine tumors during hypertensive intra-arterial chemotherapy. METHODS: Hypertensive intra-arterial chemotherapy (angiotensin II, cisplatin 100 mg, doxorubicin 40 mg) was given to two women with cervical cancer (stage IVA) and seven with endometrial cancer (three stage IA, one stage IB, two stage II, and one stage III). The intratumoral blood flow velocity waveforms were imaged by transvaginal Doppler ultrasound before and during the chemotherapy in six patients. RESULTS: The mean peak systolic velocity during hypertensive intra-arterial chemotherapy (58.9 +/- 29.3 cm/second) was significantly higher than that before chemotherapy (16.0 +/- 6.3 cm/second) (P < .05). There was a significant difference between the end-diastolic velocity before (5.2 +/- 1.8 cm/second) and during chemotherapy (21.2 +/- 6.8 cm/second) (P < .05). The resistance index value during hypertensive intra-arterial chemotherapy (0.607 +/- 0.094) fell significantly from that before therapy (0.644 +/- 0.119) (P < .05). Blood flow velocity waveforms in normal myometrial tissue could be recorded in three cases; in all, the diastolic flow noted before hypertensive intra-arterial chemotherapy disappeared during chemotherapy. CONCLUSION: These results suggest that hypertensive intra-arterial chemotherapy induces a selective marked increase of blood flow in uterine cancer.

Angiotensin II↗
PubMed1992

A critical evaluation of transvaginal Doppler studies, transvaginal sonography, magnetic resonance imaging, and CA 125 in detecting ovarian cancer.

OBJECTIVE: To evaluate whether transvaginal Doppler ultrasound is more valid than transvaginal sonography, magnetic resonance imaging (MRI), and CA 125 in differentiating malignant from benign ovarian tumors. METHODS: Sixty-three patients with ovarian tumors (36 benign and 27 malignant) were studied with transvaginal Doppler ultrasound before surgery. Blood flow velocity waveforms arising from intratumoral and/or tumor surface arteries were assessed by calculating the resistance index. Transvaginal B-mode sonography and MRI imaging examinations were also conducted. Serum CA 125 levels were measured. RESULTS: There was a significant difference between the resistance index value (0.692 +/- 0.188) in benign tumors and the value (0.503 +/- 0.107) in malignant tumors (P < .05). When 0.72 (mean of the malignant tumor resistance index values + 2 standard deviations) was considered as the cutoff value of the resistance index, the sensitivity and specificity of the resistance index in detecting malignant ovarian tumors were 92.6 and 52.8%, respectively. These values did not differ significantly from those with transvaginal sonography diagnosis (sensitivity 85.2%, specificity 69.4%). The resistance index sensitivity was significantly higher than those with MRI diagnosis (66.7%) and CA 125 levels (59.3%) (P < .05); however, the resistance index specificity was significantly lower than those with MRI diagnosis (97.1%) and CA 125 levels (91.7%) (P < .05). CONCLUSION: Our results suggest that transvaginal Doppler ultrasound does not provide more useful diagnostic information than transvaginal sonography, MRI, and CA 125 for the differentiation of malignant from benign ovarian tumors.

Adult↗