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11.
S E Bates N E Davidson E M Valverius C E Freter R B Dickson J P Tam J E Kudlow M E Lippman D S Salomon 《Molecular endocrinology (Baltimore, Md.)》1988,2(6):543-555
We have studied the estrogenic regulation and the potential autocrine role of transforming growth factor alpha (TGF alpha) in the human breast cancer cell line MCF-7. A biologically active apparent mol wt 30 k TGF alpha was identified by gel filtration chromatography in medium conditioned by MCF-7 breast cancer cells. We previously reported induction of TGF alpha levels in medium by 17 beta-estradiol. We now report correlated increases in TGF alpha mRNA, by Northern and slot blot analysis, after estrogen treatment of MCF-7 cells in vitro. In vivo experiments confirmed these data: estrogen withdrawal from MCF-7 tumor-bearing nude mice resulted in a decline in tumor size and TGF alpha mRNA levels. To explore the functional significance of TGF alpha in MCF-7 cells, anti-TGF alpha antibody was added to MCF-7 soft agar cloning assays. Inhibition of MCF-7 growth resulted, supporting an autocrine role for TGF alpha. Further experiments using an anti-EGF receptor antibody expanded this data, demonstrating inhibition of estrogen-stimulated monolayer MCF-7 cell growth. Examining the generality of TGF alpha expression, 4.8 kilobase TGF alpha mRNAs were seen in three other human breast cancer cell lines, MDA-MB-231, ZR 75B, and T47D. Expression of TGF alpha mRNA was detected in 70% of estrogen receptor positive and negative primary human breast tumors from 40 patients when examined by slot blot and Northern analysis. Thus, we have demonstrated broad expression of TGF alpha in human breast cancer, its hormonal regulation in an estrogen-responsive cell line, and its possible functional significance in MCF-7 cell growth. 相似文献
12.
13.
Respiratory resistance with histamine challenge by single-breath and forced oscillation methods 总被引:3,自引:0,他引:3
Bates J. H.; Decramer M.; Zin W. A.; Harf A.; Milic-Emili J.; Chang H. K. 《Journal of applied physiology》1986,61(3):873-880
Relaxed expirations were obtained from five anesthetized dogs under control conditions and during various rates of intravenous infusion of histamine. All volume vs. time curves obtained from 20 ms to 2 s after the start of expiration were poorly described by a single exponential function but were fitted very well by a biexponential function. The resistance of the respiratory system as a function of frequency from 2 to 26 Hz was also determined by the forced oscillation method in the same dogs. Three two-compartment models of the respiratory system were identified from the exponentials fitted to the relaxed expiration data, and the one that had the most plausible parameter values under control conditions consisted of a homogeneous lung compartment connected to a viscoelastic compartment. Although a two-compartment model is arguably appropriate for describing relaxed expirations in normal dogs, physiological considerations suggest that there should be more than two interacting components with histamine infusion. We cannot identify all these components from our data, however. The equivalent complex impedance of the respiratory system was also calculated from the biexponential curves and showed significant variation in resistance over the frequency range from 0 to 2 Hz and negligible variation above 2 Hz. The calculated resistances at 2 Hz were consistently higher than those obtained by the forced oscillation method, which may be due to the nonlinear behavior of the respiratory system during relaxed expiration. We conclude that the single-breath and forced oscillation methods should be viewed as providing complimentary information about respiratory resistance. 相似文献
14.
Physiological and isotopic aspects of several Peperomia species were investigated. All but one species had C3-like stomatal behavior, in that stomata were open during the day and closed during the night. In these species, most atmospheric CO2 uptake occurred during the day. Concurrent with this stomatal behavior, there were Crassulacean acid metabolism-like acid fluctuations in most species. Carbon and hydrogen isotope ratios of cellulose nitrate from Peperomia reflect their physiological behavior. The δ13C values of cellulose nitrate from Peperomia species were similar to values observed in C3 plants and consistent with the daytime uptake of exogeneous CO2 via the C3 photosynthetic pathway. The δD values of cellulose nitrate from Peperomia species approach those of Crassulacean acid metabolism plants. These elevated δD values are caused by fractionations occurring during biochemical reactions and not as a consequence of water relations. 相似文献
15.
Conditions for measuring fluorescence induction curves (time-scalems) of in vivo chlorophyll a were studied using cultures ofDunaliella tertiolecta Butcher (Chlorophyceae) and of Thalassiosirapseudonana Hustedt (3H) (Bacillariophyceae), and samples ofnatural phytoplankton populations from the Grand Banks. Thearea above the fluorescence induction curve (ADCMU) and themaximum fluorescence intensity (Fmax) measured in the presenceof 3-(3,4-dichlorophenyl)-1, 1-dimethylurea (DCMU) were computedby microcomputer. Cells must be conditioned oradapted prior to obtaining a fluorescence inductioncurve; dark-adaptation resulted in a lower ADCMU and Fmax thandid adaptation in far-red (720 nm) light, and was the conditioningmethod chosen. ADCMU and Fmax increased linearly with increasingirradiance up to 32.8 W m2 the highest actinic irradianceavailable. Information on the light history of D. tertiolectawas obtained by following the time-course of change in ADCMUand in Fmax for cells exposed for 10 min to far-red or to bluelight. The rise-time of the fluorescence induction curve andvalues of Fmax were greater for samples of D. tertiolecta concentratedonto glass-fiber filters than for liquid samples, however, valuesof ADCMU for filtered and liquid samples were not significantlydifferent. Samples of Grand Banks phytoplankton collected ontoglass-fiber filters and frozen for 28 d exhibited a significantdecrease in Fmax and in ADCMU relative to the same freshly-filteredsamples. Filtration and freezing of samples is not recommended.
*This paper is the result of a study made at the Group for AquaticPrimary Productivity (GAP). Second International Workshop heldat the National Oceanographic Institute. Haifa. Israel in AprilMay1984. 相似文献
16.
P J Shaw D Bates N E Cartlidge D Heaviside D G Julian D A Shaw 《BMJ (Clinical research ed.)》1985,291(6506):1384-1387
A prospective study of 312 patients undergoing elective coronary artery bypass surgery was undertaken to determine the incidence, severity, and functional impact of postoperative neurological complications. Detailed evaluation of the patients showed that neurological complications after surgery were common, occurring in 191 of the 312 patients (61%). Although such a high proportion of the total developed detectable changes, serious neurological morbidity was rare. Neurological disorders resulted in death in only one patient (0.3%) and severe disability in only four (1.3%). Forty eight patients were mildly disabled during the early postoperative period, and the remaining 138 with neurological signs had no serious functional disability. The postoperative neurological disorders detected included one death from cerebral hypoxic damage. Prolonged depression of conscious level was observed in 10 patients (3%) and definite stroke in 15 (5%); 78 (25%) developed ophthalmological abnormalities and 123 (39%) primitive reflexes; postoperative psychosis was observed in four (1%); and 37 (12%) developed disorders of the peripheral nervous system. The incidence of serious neurological problems such as fatal cerebral damage, stroke, and brachial plexopathy is in accordance with experience elsewhere. Lesser abnormalities, whose detection required detailed neurological examination, were much commoner than expected from previous reports. 相似文献
17.
Structure and synthesis of histopine, a histidine derivative produced by crown gall tumors 总被引:2,自引:0,他引:2
Histopine, an unusual amino acid derivative of histidine isolated from crown gall tumors of sunflowers (Helianthus annus) inoculated with Agrobacterium tumefaciens strain B6, was previously assigned the gross structure N-(1-carboxyethyl) histidine (2). A diastereomeric mixture containing histopine (2a and 2b) was readily prepared by reductive alkylation of (S)-histidine (1) with pyruvic acid and sodium cyanoborohydride. The individual diastereomers were prepared by reaction of (S)-histidine with (R)- and (S)-2-bromopropionic acid. (R)-N-(1-Carboxyethyl)-(S)-histidine (2a) supports the growth of A. tumefaciens whereas (S)-N-(1-carboxyethyl)-(S)-histidine (2b) is inactive. Therefore, we assign structure 2a to histopine. 相似文献
18.
A comparison of the effects of different substrata on chondrocyte morphology and the synthesis of collagen types IX and X 总被引:2,自引:0,他引:2
G. P. Bates S. L. Schor M. E. Grant 《In vitro cellular & developmental biology. Plant》1987,23(5):374-380
Summary Embryonic chick sternal chondrocytes were cultured either within three dimensional gels of type I collagen, type II collagen
or agar, or as monolayers on plastic dishes coated with air-dried films of these matrix macromolecules. It was observed that
cell shape and cell growth varied markedly between the different culture conditions. Flattened monolayers of cells on plastic
or films of type I or type II collagen, proliferated more rapidly and reached a higher final cell density per culture than
the more rounded cells found in the cultures on agar films or within three-dimensional gels. Biosynthetic studies demonstrated
that in addition to the synthesis of type II collagen, all the cultures were producing collagen types IX and X. Chondrocytes
cultured on plastic or films of the different matrix macromolecules all showed a similar expression of types IX and X collagen,
independent of whether they displayed a flattened or round cell morphology. In contrast, marked variations in the proportions
of the minor collagens, particularly type X collagen, were observed when the cells were cultured within three-dimensional
gels. The data suggest that direct interaction of the cell surface with matrix constituents displaying a particular spatial
array could be an important aspect in the control of type IX and X collagen expression by chondrocytes.
The financial support of the Arthritis & Rheumatism Council and the Medical Research Council is gratefully acknowledged. 相似文献
19.
Thermal adaptation in CHO cells at 40 degrees C: the influence of growth conditions and the role of heat shock proteins 总被引:1,自引:0,他引:1
The kinetics of thermal adaptation at the nonlethal temperature of 40 degrees C was studied in CHO (Chinese hamster ovary) cells in vitro. Thermal resistance, demonstrated as an increase in mean 45 degrees C killing time or as an increase in the shoulder of the 45 degrees C survival curve, was fully developed by 2 h. Control cells in early logarithmic phase were more heat sensitive than those in stationary phase. Corresponding 45 degrees C killing time frequency distributions were unimodal with an increase in mean killing time from early logarithmic to stationary phase. Cells which were thermally adapted at 40 degrees C for 6 h had biphasic 45 degrees C killing time frequency distributions, and as cells progressed from early logarithmic to stationary phase the heat-sensitive subpopulation progressively declined. Exposure to 40 degrees C produced a 30% increase in total protein synthesis. Proteins with molecular weights 72, 89, and 109 kDa which correspond to those induced by lethal heat shock were synthesized at 40 degrees C, but there was no close temporal correlation between the development of heat resistance at 40 degrees C and synthesis of the heat shock proteins. Cycloheximide (100 micrograms/ml) reduced the mean 45 degrees C killing time but did not totally prevent the development of heat resistance at 40 degrees C. 相似文献
20.
The effects of endotoxaemia on protein metabolism in skeletal muscle and liver of fed and fasted rats. 总被引:15,自引:6,他引:9
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The response of muscle and liver protein metabolism to either a single or three successive daily injections of an endotoxin (Escherichia coli lipopolysaccharide, serotype 0127 B8; 1 mg/ml, 0.3 mg/100 g body wt.) was studied in vivo in the fed rat, and at 24 and 30 h after endotoxin treatment during fasting. In the fed rats there was a catabolic response in muscle, owing to a 60-100% increase in muscle protein degradation rate, and a 52% fall in the synthesis rate. Although there was a 20% decrease in food intake, the decrease in protein synthesis was to some extent independent of this, since rats treated with endotoxin and fasted also showed a lower rate of muscle protein synthesis, which was in excess of the decrease caused by fasting alone. The mechanism of this decreased protein synthesis involved decreased translational activity, since in both fed and fasted rats there was a decreased rate of synthesis per unit of RNA. This occurred despite the fact that insulin concentrations were either maintained or increased, in the fasted rats, to those observed in fed rats. In the liver total protein mass was increased in the fed rats by 16% at 24 h, and the fractional synthesis rate at that time was increased by 35%. In rats fasted after endotoxin treatment the liver protein mass was not decreased as it was in the control fasted rats, and the fractional synthesis rate was increased by 22%. In both cases the increased synthesis rate reflected an elevated hepatic RNA concentration. The extent of this increase in hepatic protein synthesis was sufficient at one point to compensate for the fall in estimated muscle protein synthesis, so that the sum total in the two tissues was maintained. 相似文献