Methionine-enkephalin and beta-endorphin levels in brain, pancreas, and adrenals of db/db mice

Levels of methionine-enkephalin immunoreactivity (MEI) and beta-endorphin immunoreactivity (BEI) were measured by means of a specific RIA in pituitary, hypothalamus, pancreas, and adrenal glands of db/db and control mice. We found significantly higher levels of MEI in the pituitaries of db/db mice than in either littermate or background strain controls. There was no significant difference in MEI levels in pancreas, adrenal glands, and hypothalamus. There was a significant difference in the BEI levels in the pituitaries of db/db mice compared with those in controls. No significant difference in BEI levels was observed between db/db and control mice in any of the other regions examined. We conclude from the above data that the opiate peptide system in the hypophyseal-hypothalamic axis of the db/db mouse is abnormal and warrants further investigation. The significance of this finding with respect to the possible etiology of diabetes mellitus is discussed.

Isolation of brain fibroblast growth factor by heparin-Sepharose affinity chromatography: identity with pituitary fibroblast growth factor

Brain and pituitary fibroblast growth factors (FGF) have been purified to apparent homogeneity from crude tissue extracts by a three-step procedure, including salt precipitation, ion-exchange chromatography, and heparin-Sepharose affinity chromatography. Brain and pituitary FGF have similar amino acid compositions and are indistinguishable with respect to molecular weight (16,000 by polyacrylamide gel electrophoresis), retention behavior in reversed-phase high-performance liquid chromatography, and recognition by antibodies directed against the amino-terminal sequence of pituitary FGF. Brain FGF preparations purified by heparin-Sepharose contain, in addition to the major FGF molecular species, at least two additional forms of the growth factor, which appear to be very similar by all the above criteria, except for retention in high-performance liquid chromatography.

Electron microscopic observations of the effects of gossypol on the human endometrium

Gossypol treatment of endometriosis and uterine myomas in 15 cases was started with a daily dose of 20 mg of gossypol-acetic acid twice a day for 20 days as a loading dose, followed by 40 mg (20 mg twice weekly). A maintenance dose of 20 mg was given weekly. The total course of treatment lasted about 6 months. Light and electron microscopic examination of the endometrium was carried out before treatment and 2, 3, 4, and 6 months after gossypol treatment. After gossypol treatment three different characteristics of the endometrium were noted: (1) irregular secretory activity, (2) proliferative activity, and (3) atrophy. On electron microscopic examination it was shown that there were important changes of the organelles, indicating suppressed secretory activity. Based on the above results, the nature and significance of the ultrastructural changes of the endometrium induced by gossypol were analyzed and the possibility of developing a new field of research in female contraception with gossypol was considered.

An evaluation of the Technicon RA-1000 random-access analyzer

We evaluated the Technicon RA-1000 analyzer, with emphasis on its potential for user-defined method development. Optical linearity and sample pipetting linearity were good. The reagent pipetting system delivered slightly less than the nominal amount, owing to the volumetric effect of added mixing bubbles. Carryover of aqueous solutions was negligible. The instrument had good adaptability for user-defined methods and performed well in method comparisons. The observed dynamic range for enzymes (0-3000 U/L) was excellent. The worklisting software performed its intended functions well, but has limitations. We believe that the RA-1000 represents a significant contribution to the practice of clinical chemistry. A sophisticated benchtop machine, it includes several innovations, along with a few problems that are peculiar to its technology.

An evaluation of the Technicon RA-1000 random-access analyzer

We evaluated the Technicon RA-1000 analyzer, with emphasis on its potential for user-defined method development. Optical linearity and sample pipetting linearity were good. The reagent pipetting system delivered slightly less than the nominal amount, owing to the volumetric effect of added mixing bubbles. Carryover of aqueous solutions was negligible. The instrument had good adaptability for user-defined methods and performed well in method comparisons. The observed dynamic range for enzymes (0-3000 U/L) was excellent. The worklisting software performed its intended functions well, but has limitations. We believe that the RA-1000 represents a significant contribution to the practice of clinical chemistry. A sophisticated benchtop machine, it includes several innovations, along with a few problems that are peculiar to its technology.

Bovine brain and pituitary fibroblast growth factors: comparison of their abilities to support the proliferation of human and bovine vascular endothelial cells

The mitogenic effects of brain and pituitary fibroblast growth factors (FGF) on vascular endothelial cells derived from either human umbilical vein or bovine aortic arch have been compared. Both brain and pituitary FGF are mitogenic for low density human umbilical endothelial (HUE) cell cultures maintained on either fibronectin- or laminin-coated dishes or on biomatrices produced by cultured cells such as bovine corneal endothelial cells or the teratocarcinoma cell line PF-HR-9. Pituitary FGF triggered the proliferation of HUE cells at concentrations as low as 0.25 ng/ml, with a half-maximal response at 0.55 ng/ml and optimal effect at 2.5 to 5 ng/ml. It was 50,000-fold more potent than commercial preparations of endothelial cell growth factor and 40 times more potent than commercial preparations of pituitary FGF. Similar results were observed when the effect of pituitary FGF was tested on low density cultures of adult bovine aortic endothelial cells. When the activity of brain and pituitary FGF on low density HUE cell cultures was compared, both mitogens were active. To confirm the presence in brain extract of both acidic and neutral, as well as of basic mitogen, for HUE cells, brain tissues were extracted at acidic (4.5), neutral (7.2), and basic (8.5) pH. The three types of extracts were equally potent in supporting the proliferation of either HUE or adult bovine aortic endothelial cells. When the various extracts were absorbed at pH 6.0 on a carboxymethyl Sephadex C-50 column, the neutral and basic extracts had an activity after adsorption similar to that of unadsorbed extracts. In contrast, extracts prepared at pH 4.5 lost 90-95% of their activity which was recovered in the adsorbed fraction containing FGF.

Phosphatidyl choline and the growth in serum-free medium of vascular endothelial and smooth muscle cells, and corneal endothelial cells

Liposomes made by sonication of egg yolk phosphatidyl choline support the proliferation of low-density bovine vascular and corneal endothelial cells, and vascular smooth muscle cells maintained on basement laminacoated dishes and exposed to a defined medium supplemented with transferrin. The optimal growth-promoting effect of phosphatidyl choline was observed at concentrations of 25 micrograms/ml for low-density cultures of vascular smooth muscle cells, and 100 micrograms/ml for vascular and corneal endothelial cells. The growth rate and final cell density of vascular endothelial cells exposed to a synthetic medium supplemented with transferrin and either high-density lipoproteins or phosphatidyl choline has been compared. Although cultures exposed to phosphatidyl choline reached a final cell density similar to that of cultures exposed to high-density lipoproteins, they had a longer average doubling time (17 h vs. 12 h) during their logarithmic growth phase and a shorter lifespan (17 generations vs. 30 generations). Similar observations were made in the case of vascular smooth muscle cells or bovine corneal endothelial cells maintained in medium supplemented with transferrin, fibroblast growth factor (FGF) or epidermal growth factor (EGF), and insulin and exposed to either high-density lipoproteins or phosphatidyl choline. Since phosphatidyl choline can, for the most part, replace high-density lipoproteins in supporting the proliferation of various cell types, it is likely that the growth stimulating signal conveyed by high-density lipoproteins is associated with its polar lipid fraction, which is composed mostly of phosphatidyl cholines.

Purification in high yield of brain fibroblast growth factor by preparative isoelectric focusing at pH 9.6

The purification of fibroblast growth factor (FGF) from bovine brain has been reported (Gospodarowicz, D., Bialecki, H., and Greenburg G. (1978) J. Biol. Chem. 253, 3736-3743). Further studies have shown that bovine brain fibroblast growth factor is composed of three fragments derived by limited proteolysis from myelin basic protein (Westall, F. C., Lennon, V. A., and Gospodarowicz, D. (1978) Proc. Natl. Acad. Sci. U. S. A. 75, 4675-4678). Two of these fragments (FGF-1 and -2) had a high specific mitogenic activity. In the presence study, we have used isoelectric focusing to purify brain FGF to homogeneity. The principal active components of brain FGF preparations partially purified by gel filtration on Sephadex G-75 can be recovered in high yield from isoelectric focusing in sucrose. These components have a pI of 9.6 and 9.54, respectively. Their electrophoretic mobility, amino acid composition, and biological properties are identical with those previously reported for FGF-1 and -2.

Factors involved in the control of proliferation of bovine corneal endothelial cells maintained in serum-free medium

Experimental conditions have been defined that allow bovine corneal endothelial (BCE) cells to grow in the complete absence of serum. Low density BCE cell cultures maintained on extracellular matrix (ECM)-coated dishes and plated in the total absence of serum proliferate actively when exposed to a synthetic medium supplemented with high density lipoprotein (HDL 500 micrograms protein/ml), transferrin (10 micrograms/ml), insulin (5 micrograms/ml), and fibroblast (FGF) or epidermal growth factor (EGF) added at concentrations of 100 or 50 ng/ml, respectively. Omission of any of these components results in a lower growth rate and/or final cell density of the cultures. BCE cell cultures plated on plastic dishes and exposed to the same synthetic medium grow very poorly. The longevity of BCE cultures maintained on plastic versus ECM and exposed to serum-free virus serum-containing medium has been studied. The use of ECM-coated dishes extended the life span of BCE cultures maintained in serum-supplemented medium to over 120 generations, as compared to less than 20 generations for cultures maintained on plastic. Likewise, BCE cells maintained on ECM and exposed to a synthetic medium supplemented with optimal concentrations of HDL, transferrin, insulin, and FGF underwent 85 generations, whereas control cultures maintained on plastic could not be passaged. The enhancing effect of ECM on BCE cell growth and culture longevity clearly illustrates the importance of the cell substrate in the control of proliferation of these cells.

High density lipoproteins and the growth of vascular endothelial cells in serum-free medium

Low density bovine vascular endothelial cell cultures maintained on dishes coated with an extracellular matrix can be grown in serum-free Dulbecco's modified Eagle's medium supplemented with high density lipoprotein (HDL) and transferrin. Such cultures do not require insulin. Early passage cultures exposed to HDL and transferrin grew as well as cultures exposed to optimal serum concentrations and could be passaged repeatedly in total absence of serum. A requirement for fibroblast growth factor to ensure an optimal growth could be observed only with late-passage cultures. The present results suggest strongly that HDL is involved in supporting the proliferation of vascular endothelial cells in vitro. This may be important for our understanding of the biological role of HDL "in vivo."

Electrically controlled optical switch for multimode fiber applications

An electrically controlled optical switch based on polarization principles is described. It uses a liquid crystal twist cell that rotates polarization by 90 degrees , and it operates on an ac voltage that switches between 0.8 and 2.5 V rms. The switch has a loss of ~0.4 dB, neglecting reflections, in an unpolarized incoherent beam and a cross-talk ratio of ~-20 dB. It operates in collimated light, but it can be applied to multimode fibers using collimating lenses, which are expected to add <0.8 dB to the loss.