An activated mutant of the alpha subunit of G(o) increases neurite outgrowth via protein kinase C

The GTP-binding protein, G(o), is present at very high concentration in the neuronal growth cone membrane. The expression of activated mutants of the a subunit of G(o) increases neurite outgrowth. To determine the intracellular mechanism for this outgrowth, we have examined activated alpha o-dependent outgrowth in the presence of agents which modulate different signal transduction cascades. Activation of protein kinase C with phorbol esters or with diacylglycerol prevents the alpha o-dependent increase in neurite extension. Inhibition of protein kinase C with staurosporine, with H7, or with long-term, high dose phorbol ester treatment resulted in greater neurite elongation, and no further increase after activated alpha o transfection. The protein phosphatase inhibitor, okadaic acid, also blocked the effect of activated alpha o. In contrast, tyrosine kinase inhibitors and agents which alter cAMP levels did not alter activated alpha o-dependent neurite extension. We tested a number of compounds which alter intracellular calcium levels. TMB-8 and thapsigargin prevented an increase in outgrowth by activated alpha o, but diltiazem, Bay K8644 and dantrolene had no effect on activated alpha o-dependent outgrowth. These studies suggest that activated alpha o increases neurite outgrowth by inhibiting protein kinase C and by modulating intracellular calcium release.

Bleomycin stimulates pro-alpha 1 (I) collagen promoter through transforming growth factor beta response element by intracellular and extracellular signaling

The role of transforming growth factor beta as a mediator of the fibrogenic effect of bleomycin in lung has been investigated at the transcriptional level. Several constructs containing the rat pro-alpha 1 (I) collagen promoter fused to the chloramphenicol acetyltransferase gene were transfected into rat lung fibroblasts. Both bleomycin and transforming growth factor beta 1 increased promoter activity in fibroblasts transfected with constructs containing the transforming growth factor beta response element. Fibroblasts transfected with a deletion construct that lacks this response element did not respond to either bleomycin or transforming growth factor beta 1. Anti-transforming growth factor beta 1-neutralizing antibodies did not block the increase in promoter activity induced by bleomycin, suggesting intracellular signaling. Mutation of the transforming growth factor beta response element greatly reduced the bleomycin effect, which also infers intracellular signaling. In addition, plasmin added to the media greatly enhanced bleomycin stimulation of promoter activity demonstrating that transforming growth factor beta mediates the bleomycin effect through extracellular signaling.

Percutaneous transseptal balloon valvuloplasty for dilating mitral valve stenosis (report of 200 cases)

Two hundred cases with mitral valve stenosis were treated by percutaneous single balloon (Inoue balloon) valvuloplasty at our institute from May 1988 to July 1992. The subjects included 137 females and 63 males with a mean age of 36.5 +/- 8.8 years (15-58 years). Hemodynamic and left ventriculographic findings were evaluated immediately before and after the procedure, and the results showed that the mean left atrial pressure was reduced from 25.08 +/- 9.13 mmHg to 10.64 +/- 4.10 mmHg (P < 0.001), the pressure gradient across the mitral valve was reduced from 25.49 +/- 10.22 mmHg to 6.71 +/- 4.87 mmHg (P < 0.001), and systolic pulmonary pressure was reduced from 52.78 +/- 21.42 mmHg to 38.56 +/- 16.47 mmHg (P < 0.001). At the same time, cardiac output and mitral orifice area were increased from 3.84 +/- 0.11 L/min to 4.66 +/- 0.28 L/min (P < 0.001) and from 1.08 +/- 0.28 cm2 to 2.20 +/- 0.47 cm2 (P < 0.001) respectively. Follow-up of 6-48 months (median 24 months) in 50 nonselective patients showed a symptomatic improvement rate of 100%. Percutaneous transseptal balloon mitral valvuloplasty (PBMV) proved to be a highly effective and safe nonsurgical method that can yield very good results in relieving symptomatic rheumatic mitral stenosis, with minimal morbidity and no mortality in this group. PBMV works by splitting the adhered mitral commissures toward the mitral annulus.

A case-control study of dietary factors in patients with lung cancer

A case-control study was designed to investigate association of dietary factors with the risk of lung cancer in Sichuan, China. The cases consisted of 135 patients with preinvasive lung cancer which had been confirmed with histopathology, fiber bronchoscope, CT and X-ray film in three provincial hospitals in the recent one year. Controls were healthy subjects who went to one of these hospitals for health check-up; patients with pulmonary diseases was excluded. Controls were matched to cases for sex and age with a ratio of 1:1. Nutrient intakes, the eating habit and other relevant factors were investigated. The data analyzed with the conditional logistic regression model indicated that dietary beta-carotene intakes had a significantly inverse association with the risk of lung cancer. Vitamin C had a less significantly inverse association with the risk. Association of protein, fat, energy, retinol intakes or diet-balance index with the risk was not significant. Association of tea, alcohol, garlic or mushroom, respectively, with the risk was also not observed. Consumption of more processed foods and deep-fried foods were found to be risk factors. Smoking and air pollution from coal burning stoves were also observed as independent risk factors of lung cancer in the present study. The mental stress incidence in the case was significantly higher than that in the control.

Studies on the photochemical and photocytotoxic properties of the new PDT photosensitizer aluminum sulfonated phthalocyanine

The properties of photosensitization of sulfonated aluminum phthalocyanine (ALSPC), a new photosensitizer of potential use in cancer photodynamic therapy (PDT) was studied on both the molecular and cellular levels. The mechanism of ALSPC photosensitization on the molecular level was investigated by testing its efficiency of singlet oxygen (1O2) production, using the method of tryptophan degradation and that of ESR spectroscopy and observing the enhancing effect of D2O and the quenching effect of NaN3. Results of all these experiments confirmed the important role of the Type II or 1O2 mechanism in ALSPC photosensitization. In our in-vitro experiments, ALSPC's incorporation into cells and its photocytotoxic effect were investigated on a human liver cancer cell line. The cell incorporation was illustrated by the laser-excited fluorescence spectra emitted both from cell homogenate and cell monolayers incubated with ALSPC aqueous solution. The position of fluorescence peak observed, implied that ALSPC exists in the cells mainly as monomers. The efficiency of cell killing of ALSPC photosensitization was estimated by counting surviving cells with the method of trypan blue staining and by the method of radioisotope labelling. Experiments using the latter method also showed DNA damage caused by ALSPC photosensitization.

Survey of the use of epidural analgesia in China

It is generally believed that epidural blocks are most widely used in China. However, there is yet no substantial study in this respect. A nation-wide survey appears to be necessary. Questionnaires were sent to 237 hospitals located in 6 geographically wide-scattered areas and to some military hospitals as well. 90 answers were obtained with complete data necessary for this survey. There are 1,304,214 administrations of epidural blocks documented in these 90 hospitals. Of which 38.8% are lumbar, 32% lower thoracic, 23% middle thoracic, 4.6% upper thoracic and 1.6% cervical blocks. These data showed that operations from the neck down to the lower extremities were performed under epidural block without discrimination of puncture location. 98.33% of the blocks were satisfactory to meet the need of operations. Persisting paresthesia occurred in 0.013% of these cases. The incidence of accidental puncture of dura was 0.32%. About 2/3 of these dura punctured cases received 1-4 times of repuncture. No correlation was found between repuncture and development of total spinal anesthesia. Among the complications, incidence of respiratory depression was 0.54%. However, only 5% of these depressed cases needed intubation and artificial ventilation. No signs of dura puncture were noticed, but subarachnoid block did appear in 0.04 of cases. Incidence of total spinal anesthesia was 0.013%. Not all, but a little more than half (54.6%) of the total spinal cases needed intubation and artificial ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

[Experimental study on capacity of lung water regulation]

The capacity of the regulation of lung water after fluid overloading or blood letting was measured in 70 rabbits. Body fluid in the whole blood was increased in both overloading and blood letting. The lung blood volume was increased after crystalloid overloading, but statistically insignificant (P greater than 0.05). On the contrary, a very significant (P less than 0.01) increase of lung blood volume was observed in all animals overloaded with colloid fluids. Blood letting caused an insignificant (P greater than 0.05) decrease of lung blood volume. Total lung water was increased in either groups, but, it was statistically insignificant in crystalloid group and highly significant in crystalloid group. Colloid fluid overloading caused a marked increase (P less than 0.01) of extravascular lung water (EVLW). Interesting to note is that animals received crystalloid fluids amounted up to 3-fold of its blood volume did not show any significant (P greater than 0.05) increase of EVLW. It is concluded that the capacity of lung water regulation was extraordinary intact even after the overloading with crystalloids in an amount equivalent to 2.5-fold of its blood volume. This phenomenon was not seen in the colloids group.

[An experimental study on photosensitization of human liver cancer cells with sulfonated aluminum phthalocyanine (ALSPC)]

The photosensitizing effect of sulfonated aluminum phthalocyanine to human liver cancer cells was studied by determining the kinetics of its cellular uptake, its state of aggregation therein and its photocytotoxicitic effect on these cells. Fluorescence methods were used to measure the cellular uptake in cell extracts and intact cells in monolayer. Results exhibited that the cellular uptake increases with the incubation time of ALSPC and saturates at 24 hrs. This relation was in coincidence with that between ALSPC's photocytotoxic effect and the ALSPC incubation time. Although the average ALSPC concentration in cells is higher than the incubation concentration of ALSPC, laser fluorescence, experiments showed that the fluorescence peak of ALSPC in cells incubated in higher concentration coincides with that of its aqueous solution of low concentration, suggesting that ALSPC in cancer cells exists in monomer state. Characteristics of the photodamaging effect of ALSPC to cancer cells were studied by both the method of typen blue staining and that of isotope labeling, which showed similar results. Results of the isotope labeling experiments implies that the DNA is damaged in ALSPC photosensitization. The photodamage on cells was also studied with 3 T 3 mouse cells (conversion), showing agreeable results to that with liver cancer cells, which suggests that ALSPC's photocytotoxic effect is nonselective to cell types.