Inhibition of IL-1-induced IL-6 production by synthetic retinoids

The effects of retinoids and retinoid antagonists on IL-6 production in MC3T3-E1 cells were investigated. None of the synthetic retinoids examined stimulated IL-6 production, but all of them strongly inhibited IL-6 production induced by mouse IL-1 alpha. Their inhibitory activities correlated well with their differentiation-inducing activities in HL-60 assay or their binding affinities to nuclear retinoic acid receptors (RARs). Among three retinoid antagonists, two weak antagonists exhibited similar inhibition of mouse IL-1 alpha-induced IL-6 production, whereas a potent retinoid antagonist, 4-(13H-10,11,12,13-tetrahydro-10,10,13,13,15-pentamethyl-dinaph tho[2,3-b] [1,2-e]diazepin-7-yl)benzoic acid (LE540, 14), enhanced IL-6 production under the same conditions.

Effect of vapor pressure deficit on spinach growth under hypobaric conditions

The effect of vapor pressure deficit (VPD) of air during photoperiod on spinach growth under low total pressure was examined. Spinach plants grown under atmospheric pressure were transplanted into a pressure-reduced growth chamber and cultured hydroponically for eight days. The air temperature in the growth chamber was kept at 25 degrees C during the light period and 20 degrees C during the dark period. In the control, the total pressure was 101 kPa and the VPD was 0.95 kPa. The low pressure treatment had a total pressure of 25 kPa and a VPD of 0.95 kPa. The low pressure and high humidity treatment had a total pressure of 25 kPa, and a VPD of 0.48 kPa. The VPD during the dark period was consistent for all treatments at 0.44 kPa. O2 and CO2 partial pressures were constant at 21 kPa and 40 Pa, respectively. The photosynthetic photon flux density (PPFD) on a plant bed inside the growth chamber was 250 micromoles m-2 s-1 on a plant bed. Relative growth rate (RGR) of spinach in the low pressure and high humidity treatment was significantly greater than in the control. There was no significant difference in RGR between the control and the low pressure treatment. The low pressure and high humidity treatment also had increased leaf area. These results showed that the effect of pressure alone was not significant on RGR, but the combination of low pressure with high humidity was important.

Evaluation of differentiation-inducing activity of retinoids on human leukemia cell lines HL-60 and NB4

Retinoids, including all-trans-retinoic acid (ATRA), its isomers, and fifty synthetic retinoids (retinobenzoic acids), were tested for differentiation-inducing activity on human leukemia cell lines HL-60 and NB4. Binding activity of typical retinoids to nuclear retinoic acid receptors (RARs) was also investigated. A good linear correlation between the ED50 values of differentiation-inducing activity towards HL-60 cells and those towards NB4 cells was found. Binding activities of retinoids to RAR alpha and RAR beta also correlated well to the differentiation-inducing activities.

Cancer-associated retinopathy with presumed vasculitis

PURPOSE

To treat a 63-year-old woman who experienced fairly rapid vision loss in association with small-cell carcinoma of the lung.

METHODS

She underwent a full ophthalmologic examination, including fluorescein angiography and an immunologic study by Western blot analysis.

RESULTS

Fluorescein angiography demonstrated diffuse staining of the retinal vessels. She had 62-kd antiretinal antibody in her serum. Cancer-associated retinopathy was diagnosed.

CONCLUSION

The staining seen on the angiogram appears to indicate vasculitis, which would cause the characteristic attenuation of retinal vessels in this disease.

Correlation of differentiation-inducing activity of retinoids on human leukemia cell lines HL-60 and NB4

Retinoids, including all-trans-retinoic acid, its isomers, and fifty synthetic retinoids (retinobenzoic acids), were tested for differentiation-inducing activity on human leukemia cell lines HL-60 and NB4. A good linear correlation, with an r value of 0.91, between the ED50 values for the differentiation-inducing activity towards HL-60 cells and that towards NB4 cells was found.

Suppression of plasma glutathione peroxidase activity by ifosfamide

Plasma glutathione peroxidase (GPx) is synthesized predominantly in the kidneys. Plasma-GPx activities were measured in 12 patients with gynecological malignancies before and after chemotherapy. The patients were treated with cisplatin alone (P); with VP16 and cisplatin (EP); with cyclophosphamide, doxorubicin, and cisplatin (CAP); or with ifosfamide, doxorubicin, and cisplatin (IAP). The protein levels of the enzyme were semi-quantitatively determined by immuno-blot analysis. Plasma GPx activity was decreased by an average of 61% (p < 0.01) in patients treated with IAP, while no significant decreases were observed in patients treated with any drug combinations without ifosfamide. Immuno-blot analysis of plasma samples from a patient treated with IAP revealed no differences in the protein levels of plasma GPx either before or after IAP administration, although the plasma GPx activity decreased 83%, from 0.173 to 0.029 units/ml. The results indicate that the decrease in plasma GPx activity was not due to impaired production of the enzyme in the kidneys, and that ifosfamide is responsible for inhibition of the enzyme activity. Since GPx is an enzyme of major importance in detoxification of lipid peroxides in the brain, CNS toxicity induced by ifosfamide might be related to severe suppression of plasma GPx activity.

[Prediction of lowest PaO2 during unilateral whole lung lavage in a patient with pulmonary alveolar proteinosis--unilateral ventilation with nitrogen]

Unilateral whole lung lavage (UWLL) was performed four times in a patient with pulmonary alveolar proteinosis. PaO2 was 94 Torr even under ventilation with 100% O2. Because of the difficulty in providing adequate arterial oxygenation, extracorporeal membrane oxygenation (ECMO) was indispensable in accomplishing the first right UWLL. During the second left UWLL, the left lung was ventilated with nitrogen (N2) and an attempt was made to predict the lowest PaO2 occurring during lavage in order to establish criteria for the use of ECMO during UWLL. When both lungs were ventilated with 100%. O2, PaO2 rose to 150 Torr. PaO2 fell to 65 Torr after ventilation of the left lung with N2 while the right lung was ventilated with 100% O2 for 7 minutes. The N2 was replaced with 100% O2 and ventilation was continued for another 10 minutes to wash the N2 out of the left lung. When the tracheal tube in the left lung was clamped for 7 minutes for degassing, PaO2 fell to 59 Torr. Subsequently 1,200 ml of physiological saline was injected into the left lung, and PaO2 rose to 155 Torr. A 6 Torr difference was found between the value of PaO2 under ventilation with N2 and that of degassing, but this difference was not statistically significant. The lowest PaO2 occurring during UWLL was considered to be predictable if the unilateral lung was ventilated with N2.