The effect of intrauterine devices, the stainless steel ring, the copper T220, and releasing levonorgestrel, on the bleeding profile and the morphological structure of the human endometrium--a comparative study of three IUDs. A morphometric study of 96 cases

Thirty-four women using the stainless steel ring (SS), 43 women using the Copper T220 (TCu), and 19 women using levonorgestrel-releasing intrauterine devices (LNG) were admitted to the study. The light microscopic biopsy material was subjected to morphometric studies including 8 indices of endometrial activity before (Control) and after 24 months of exposure to the SS and TCu device and 3-10 months of exposure to the LNG device. The women were grouped into subjects with and without intermenstrual and prolonged bleeding. The results revealed that there were highly significant differences between the IUDs at the endometrial level as displayed by morphometry. However, the difference between bleeders and non-bleeders was not significant in any of the three types of IUDs. Although the mode of action of these IUDs at the endometrial level is different, the mechanism responsible for the irregular endometrial bleeding needs to be further investigated.

Cyclosporin in the treatment of severe aplastic anemia: report of one case

According to recent reports, cyclosporin (CsA) has been proven to be a cure for some patients with severe aplastic anemia (SAA). The use of CsA to treat SAA is based on both experimental and clinical evidences showing that this disease is sometimes caused by immune-mediated mechanisms. This report describes a fourteen-year-old boy who recovered from SAA after being treated with CsA, together with to a lesser extent prednisolone. In June of 1986, when he failed to improve after receiving six months of corticosteroid treatment, CsA was introduced. Following three weeks of CsA therapy no further blood transfusion was needed. Danazol was added on the 28th day of CsA therapy. On the 105th day the blood counts began to improve, and on the 375th day bone marrow aspirate revealed normal hematopoiesis. Along with these improvements, however, some side effects from the CsA treatment were observed. These included: hirsutism, hypertension and gingival hyperplasia, all of which eventually subsided on tapering and finally terminating CsA. For the time being, no side effects have been observed in the six-months period since CsA was stopped and the patient is leading a normal life.

Heat stroke: a clinical review of 27 cases

Heat stroke is the most serious entity amongst the heat disorders. Whilst potentially fatal, it is preventable and salvageable. A retrospective study involving 27 patients admitted for exertional heat stroke to the Medical Unit, Toa Payoh Hospital, Singapore from January, 1984 to January, 1987 was carried out. These patients presented with a rectal temperature of greater than 40 degrees C and central nervous system disturbances. All were males and, except for three, were local born. All except two were below thirty years old. The patients were treated with a standard regime of IV fluids and sponging in the ICU. 19 patients (70.4%) presented in coma whilst abnormal behaviour, e.g. aggression and mental confusion was seen in the remainder. Fits were seen in only 5 patients (18.5%). Metabolic acidosis was seen in 93.3%. Hypokalaemia was present in 3 patients (11.1%). Of the enzymes, creatinine phosphokinase was elevated in all except 1 patient (mean: 4868.8, range: 146-28850). There were no deaths recorded in this series. Complications include reversible DIVC (3 instances), oliguric renal failure (4 instances) and residual neurological deficit (2 instances). 9 patients (39.1%) took more than 4 hours for the rectal temperature to attain 37.5 degrees C. All the above complications except for 1 instance of DIVC occurred in this group with delayed cooling. Heat stroke is a serious condition with serious complications and require prompt treatment.

Vagal stimulation decreases rate of left ventricular relaxation

We determined the effects of vagal stimulation on the time constant (tau) of left ventricular isovolumic pressure decay and on the maximum rates of left ventricular pressure change (dP/dt) during contraction and relaxation in anesthetized dogs. In each dog, the atria were paced at a constant rate of 150 beats/min. We recorded left ventricular pressure waveforms in the absence (control) and in the presence of vagal stimulation at frequencies of 1, 2, and 3 Hz. During the control periods and during vagal stimulation at each frequency, we determined tau, the maximal rate of contraction, and the maximal rate of relaxation from left ventricular pressure waveforms recorded at medium (100 mmHg), high (130 mmHg), and low (73 mmHg) afterloads. Vagal stimulation at a frequency of 3 Hz increased tau by 23%. This effect of vagal stimulation on tau was most pronounced at the high afterload. Vagal stimulation at 3 Hz decreased the maximal rate of relaxation by 19%, but it decreased the maximal rate of contraction by only 8%. Thus vagal stimulation significantly decreased the rate of left ventricular relaxation and had a greater depressant effect on ventricular relaxation than on contraction.

Post-treatment calcification of mesenteric non-Hodgkin lymphoma: CT findings

We report the clinical course, plain radiographic, and CT findings in two cases of post-treatment calcification in non-Hodgkin lymphoma. A peripheral curvilinear pattern of calcification appears to be characteristic.

In situ correlative immuno-identification of mononuclear infiltrates and invasive bacteria in diseased gingiva

The purpose of this study was to identify and quantify mononuclear cells and invasive bacteria in consecutive histological sections in diseased gingiva. Gingival biopsies were obtained from sites displaying evidences of severe periodontitis (pocket depth greater than 5 mm, bleeding on probing) in six patients. Specimens were frozen and serially sectioned at 8 micron in a cryostat. Monoclonal antibodies (mAb) directed against membrane markers of mononuclear infiltrate cells and rabbit polyclonal sera against specific bacteria shown to be invasive in association with an immunoperoxidase technique and specific point quantification were used. The mAb panel included Leu 1 (Pan T), Leu 2a (T suppressor/cytotoxic), Leu 3a (T helper/inducer), Leu 6 (Langerhans/dendritic), Leu 7 (NK/K), Leu M3 (monocyte/macrophage), and B7 (B cell). This methodology allows for in situ per cent quantification of mononuclear cell subsets along with identification and quantification of invasive bacteria in the same gingival tissue site. This may be a practical approach to establish the relationship between bacterial invasion and cellular immune response by the host. This technique enabled the characterization of the mononuclear infiltrate in relationship to specifically identified invasive bacteria in diseased gingiva.

Brain neurotransmitters in glycine encephalopathy

We measured neurotransmitter markers in autopsied brain of infants with glycine encephalopathy (GE). Because patients with GE develop intractable seizures, special attention was devoted to those neurotransmitter systems implicated in human epilepsy. Mean levels of glycine in the frontal cortex of GE patients were three times higher than control values. No abnormalities were observed for concentrations of gamma-aminobutyric acid (and related receptors), other major neurotransmitter amino compounds, or activities of cholineacetyltransferase and aspartate aminotransferase. Mean acetylcholinesterase activity was significantly elevated by 46%. As experimental data suggest, glycine markedly potentiates the action of the excitatory neurotransmitter glutamic acid. To the extent that the brain seizures in patients with GE can be explained by this mechanism, pharmacotherapy with excitatory amino acid antagonists may represent a new approach to the treatment of GE.

[Histamine and lung cancer. II. Human lung cancer cell line and histamine]

Using tissue culture and biochemical technique, the effects of autacoid-histamine and histamine H-2 receptor's antagonist-cimetidine on human lung cancer cell line were studied. It was shown that histamine at the concentration of 1.8 x 10(-7) M stimulated proliferation of the lung cancer cells, but histamine at the concentration of 1.8 x 10(-4) M or cimetidine at 1.76 x 10(-7) M inhibited growth of the lung cancer cells. Relation between histamine, histidine decarboxylase, histamine formation capacity and tumor proliferation is discussed.

Increased heart rate accelerates norepinephrine washout from normal myocardium

We determined whether a change in heart rate affected the decay of the ventricular inotropic response to sympathetic stimulation in an experimental group and in a control group of anesthetized dogs. We induced complete heart block in each animal and paced the ventricles at rates of 90, 120, and 150 min-1 during two observation periods. In the experimental group, desipramine hydrochloride was given during the second period to block the neuronal uptake mechanism. The control animals did not receive desipramine during either period. The time required for the ventricular inotropic response to decay by 50% after cessation of a 2-min train of sympathetic stimulation was used as an index of the rate of norepinephrine washout from the myocardial interstitium. As we increased the pacing rate over the range of 90-150 min-1 in the experimental group, the mean decay half times (+/- SE) decreased by 36 +/- 4% (P less than 0.001) before desipramine and by 26 +/- 6% (P less than 0.001) in the presence of desipramine. These decrements in the decay half times were not significantly different from each other. The mean decay half times decreased by 36 +/- 4% (P less than 0.001) in the control dogs; the effects did not change appreciably from the first to the second observation period. We conclude that an increase in pacing frequency facilitates the washout of norepinephrine from the ventricular myocardium; this facilitation is equally pronounced regardless of whether the neuronal uptake mechanism is intact or suppressed.

Growth of myoblasts in lipoprotein-supplemented, serum-free medium: regulation of proliferation by acidic and basic fibroblast growth factor

BC3Hl myoblast cells seeded at low density on gelatin-coated dishes and exposed to a 1:1 (vol/vol) mixture of Dulbecco's modified Eagle's medium and Ham's F12 medium, proliferate actively when exposed to high density lipoproteins (HDL), transferrin, insulin, and basic or acidic fibroblast growth factor (FGF). This serum-free medium combination supported cell multiplication at a rate equal to that of serum-supplemented medium, and at low cell input (10(3) cells/35-mm dish). It also allowed serial transfer of the cultures under serum-free conditions. HDL seems to promote cell survival and to act as progression factor allowing cells to divide when exposed to either basic or acidic FGF. When the potency of basic and acidic FGF were compared, acidic FGF was 20-fold less potent than basic FGF.

Surgery for neglected congenital torticollis

Nineteen patients were operated on for congenital muscular torticollis after the age of 1 year. Tenotomy gave good results below 5 years of age and resection of the sternocleidomastoid muscle was satisfactory in most of the older children.

Inhibition of excitatory neurotransmission with kynurenate reduces brain edema in neonatal anoxia

Excitatory amino acid neurotransmitters have been implicated in fostering brain edema and neuronal death in ischemia. As both of these processes are involved in nervous system damage during neonatal anoxia, the effect of blockade of cell excitation with kynurenate upon brain water was studied following anoxic-ischemic brain injury in neonatal rats. Such treatment attenuated brain edema immediately after, and 24 h following anoxia-ischemia.

Heparin protects basic and acidic FGF from inactivation

The ability of heparin or that of hexuronyl hexosaminoglycan sulfate (HHS-4) to protect basic or acidic fibroblast growth factor (FGF) from acid or heat inactivation has been analyzed. Both freshly prepared basic and acidic FGF stimulate the growth of baby hamster kidney (BHK-21) cells exposed to medium supplemented with transferrin and insulin. Freshly prepared basic FGF was 10 fold more potent than acidic FGF. The addition of heparin to the medium decreased the potency of basic FGF while it potentiated that of acidic FGF. Upon storage of FGF at -80 degrees C, a decline in potency of both basic and acidic FGF was observed. Heparin, when added to the medium, potentiated their activities, which became similar to that of freshly prepared basic FGF. In order to test whether heparin could protect basic or acidic FGF from inactivation, both mitogens were exposed to acid conditions (1% trifluoroacetic acid, pH 1.08, 2 h) or heat (65 degrees C, 5 min) which inactivate basic or acidic FGF. When exposed to such treatment in the presence of heparin or HHS-4, basic and acidic FGF retained their potency. The effect of heparin and HHS-4 on the bioactivity of basic and acidic FGF is truly of a protective nature, since they had no effect when added after inactivation of the mitogens. Potentiation of the bioactivity of the protected mitogens or of the inactivated one could only be observed when cells were exposed to high heparin or HHS-4 concentrations. This indicates that heparin and HHS-4, in addition to protecting FGF from inactivation, also acts at another locus, as yet unidentified.

Effect of retina-derived basic and acidic fibroblast growth factor and lipoproteins on the proliferation of retina-derived capillary endothelial cells

Retina-derived capillary endothelial (RCE) cells have been established in culture, taking advantage of their ability to proliferate at clonal density when maintained on extracellular matrix (ECM)-coated dishes in the presence of serum-supplemented medium. This cell type formed at confluence a monolayer of small, tightly packed, contact inhibited cells which expressed Factor VIII-related antigen. Both retina-derived basic and acidic fibroblast growth factors (FGF) were mitogenic when RCE cells were maintained on gelatin-coated dishes and exposed to serum-supplemented medium. Half-maximal stimulation of cell proliferation was observed with concentrations of 13 pg ml-1 for basic FGF and 2.5 ng ml-1 for acidic FGF. Maintaining RCE cells on extracellular matrix (ECM)-coated dishes greatly reduced their requirement for EGF in order to proliferate actively. Heparin strongly reduced the proliferative response of RCE cells to either basic or acidic FGF, as well as their response to serum alone, regardless of whether cells were maintained on gelatin or on ECM-coated dishes. When RCE cells maintained on ECM-coated dishes were exposed to defined medium, high density lipoproteins, transferrin, and FGF were required in order for these cells to proliferate actively.

Effect of fibroblast growth factor and lipoproteins on the proliferation of endothelial cells derived from bovine adrenal cortex, brain cortex, and corpus luteum capillaries

Bovine adrenal and brain cortex and corpus luteum-derived capillary endothelial cells have been established in culture, taking advantage of their ability to proliferate at clonal density when maintained on extracellular matrix (ECM) coated dishes in the presence of serum supplemented medium. All three cell types formed at confluency a monolayer of small, tightly packed, contact inhibited cells that express factor VIII related antigen. Their proliferative response to basic and acidic FGF when cells were maintained on plastic and exposed to serum supplemented medium was similar to that previously reported for endothelial cells derived from large vessels, with acidic FGF being 30-fold less potent than basic FGF. Their requirement for high density lipoproteins and transferrin in order to proliferate actively when maintained on ECM-coated dishes and exposed to serum-free conditions was also similar to that previously reported for endothelial cells derived from large vessels. Heparin strongly reduced the proliferative response of capillary endothelial cells to either basic or acidic FGF, as well as their response to serum alone, regardless of whether cells were maintained on plastic or on ECM-coated dishes. The present data indicate that bovine endothelial cells derived from large or small vessels are indistinguishable in so far as their response to growth factors, plasma factors, and substrata are concerned.

Isolation of fibroblast growth factor from bovine adrenal gland: physicochemical and biological characterization

The angiogenic growth factors present in the bovine adrenal gland have been purified by a combination of differential salt precipitation, ion exchange chromatography, and heparin-Sepharose chromatography. They consist of 2 single chain polypeptides with apparent mol wt of 16,000 and 15,000. Sequence analysis of the first 14 residues of both peptides identified the sequences as Pro-Ala-Leu-Pro-Glu-Asp-Gly-Gly-Ser-Gly-Ala-Phe-Pro-Pro for 1 of the peptides and His-Phe-Lys-Asp-Pro-Lys-Arg-Leu-Tyr-x-Lys-Asn-Gly-Gly for the other. The first sequence is identical to residues 1-14 of bovine pituitary and brain fibroblast growth factor (FGF), while the second is identical to residues 1-14 of the corpus luteum (CL) FGF, which is an amino-terminally truncated form of FGF and is otherwise similar, if not identical, to FGF. The biological activity of adrenal FGF is indistinguishable from that of pituitary or brain FGF and CL FGF. They are highly active in triggering the proliferation of culture bovine vascular endothelial cells derived from either large vessels (aortic arch) or CL and adrenal cortex capillaries (half-maximal stimulation at 20-40 pg/ml and saturation at 400-600 pg/ml). In vivo implants containing 50 ng to 1 microgram adrenal-derived growth factors stimulate neovascularization in the chorioallantoic membrane of the chick embryo. In addition to being mitogenic for vascular endothelial cells, adrenal FGFs stimulate the proliferation of a wide variety of mesoderm- and neuroectoderm-derived cells, including vascular smooth muscle cells, granulosa and adrenal cortex cells, rabbit costal chondrocytes, and corneal endothelial cells.

Corpus luteum angiogenic factor is related to fibroblast growth factor

An angiogenic growth factor present in bovine corpus luteum (CL) has been purified to apparent homogeneity by a combination of differential salt precipitation, ion exchange chromatography, and heparin-Sepharose chromatography. It is a single chain polypeptide with an apparent mol wt of 15,000 and an amino acid composition similar to that previously reported for pituitary and brain fibroblast growth factor (FGF). Sequence analysis of the first 17 residues of the CL-derived growth factor identified the sequence; His-Phe-Lys-Asp-Pro-Lys-Arg-Leu-Tyr-X-Lys-Asn-Gly-Gly-X-Phe-Leu. This sequence is identical to residues 16-33 of bovine pituitary and brain FGF, indicating that the CL-derived growth factor is an amino-terminally truncated form of FGF and is otherwise similar, if not identical, to FGF. The biological activity of CL FGF is indistinguishable from that of pituitary or brain FGF. It is highly active in triggering the proliferation of cultured bovine vascular endothelial cells derived either from large vessels (aortic arch) or from corpus luteum and adrenal cortex capillaries (half-maximal stimulation at 20-40 pg/ml and saturation at 400-600 pg/ml). In vivo implants containing 50 ng to 1 microgram CL-derived growth factor stimulate neovascularization in the chorioallantoic membrane of the chick embryo. In addition to being mitogenic for vascular endothelial cells, CL FGF also stimulates the proliferation of a wide variety of mesoderm- and neuroectoderm-derived cells, including vascular smooth muscle cells, granulosa and adrenal cortex cells, rabbit costal chondrocytes, and corneal endothelial cells.

Fibroblast growth factor in the human placenta

Fibroblast growth factor (FGF) has been purified 333,000-fold from human placenta by a combination of salt precipitation, cation-exchange chromatography, and Heparin-Sepharose affinity chromatography. Molecular weight (15-16 kDaltons), amino acid composition, bioactivity and immunological crossreactivity with bovine pituitary FGF indicate that the mitogens from the two species are closely related molecules.

Isolation of pituitary fibroblast growth factor by fast protein liquid chromatography (FPLC): partial chemical and biological characterization

Bovine pituitary fibroblast growth factor has been purified 222,000-fold to homogeneity by a combination of differential salt extraction, gel filtration, and ion exchange chromatography on Mono S column. Pituitary FGF is a single-chain polypeptide with an apparent molecular mass of 15,800 and an isoelectric point of 9.6. It is highly active in triggering the proliferation of bovine and human vascular endothelial cell [half-maximal stimulation at 23-40 pg/ml (1.5-2.6 pM) and saturation between 140 and 280 pg/ml (9.3-18.6 pM)]. It displays a similar activity on bovine vascular smooth muscle cells, corneal endothelial cells, granulosa and adrenal cortex cells, and rabbit costal chondrocytes.

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.