Stable murine chondrogenic cell lines derived from c-fos-induced cartilage tumors

This study describes the detailed characterization of four murine chondrogenic cell lines (wT2-1, wT2-7, wT2-8, and wT2-9) that were isolated from a cartilage tumor induced by the protooncogene c-fos in chimeric mice. All cell lines are clonal and display a fibroblastic morphology with a doubling time of 1-2 days. Northern blot analysis demonstrated that in addition to expressing high levels of exogenous c-fos, all clones express varying levels of the cartilage marker gene type II collagen in addition to type I collagen. The clones also expressed high levels of the AP-1 genes c-jun and fra-1. The doubling times of these clones did not change over a period of 14 months in culture. Most importantly, however, expression of type II collagen was maintained in all cell lines for 8 months in culture, and two cell lines maintained type II collagen expression when analyzed after 14 months. Interestingly, type I collagen expression was lost after long-term culture. Following injection into syngeneic and nude mice, all cell lines formed tumors containing areas with the morphologic appearance of hyaline cartilage, indicating that these cell lines are chondrogenic. Thus, these stable murine chondrogenic cell lines provide a useful tool for studying the transcriptional control of cartilage-specific gene expression, as well as the growth control of chondrogenic cells.

Beneficial acute effects of selective modulation of renal dopamine system by gamma-L-glutamyl-L-dopa in rabbits with congestive heart failure

gamma-L-Glutamyl-L-dopa (gludopa) is a dopamine (DA) prodrug with a high degree of renal selectivity. We compared the acute renal effects of gludopa in conscious control rabbits (n = 6) and rabbits with doxorubicin-induced congestive heart failure (CHF, n = 5). Normal saline and gludopa 25 and 100 micrograms/kg/min were infused intravenously (i.v.), each for 60 min. One week later, the same protocol was followed except that the DA-1 antagonist SCH 23390 was given i.v. in a dose of 0.3 mg/kg 10 min before gludopa infusion. An additional control group (n = 6) received the DA-1 antagonist alone and saline vehicle infusion throughout the study period. In both control and CHF groups, gludopa elicited significant and similar increases in urine flow (70, 62%), sodium excretion (127, 98%), and renal blood flow (RBF) (33, 27%), and decreased renal vascular resistance (RVR) (-23, -38%). All these changes were abolished by previous DA-1 antagonism with SCH 23390. Blood pressure (BP), heart rate (HR), and hindlimb blood flow (HBF) remained unchanged during gludopa infusion in both groups. In the control group, but not in the CHF group, plasma renin activity (PRA) increased during gludopa infusion; this was not influenced by DA-1 antagonism. In normal rabbits (n = 6), treatment with SCH 23390 alone had no significant effect on renal excretory function or haemodynamics. During gludopa administration, plasma DA concentration was not significantly altered, whereas urine DA excretion and renal DA content were markedly increased. Intrarenal conversion of gludopa to DA was significantly less in CHF rabbits as compared with the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

The dopamine prodrug, gludopa, decreases both renal and extrarenal noradrenaline spillover in conscious rabbits

1. Renal and total noradrenaline (NA) spillover rates were examined under control conditions and during graded infusions of gludopa (gamma-L-glutamyl-L-dopa) in conscious rabbits. 2. Gludopa infusion at 25 and 100 micrograms/kg per min did not alter mean arterial pressure (MAP) and heart rate (HR), but had significant dose-related effects on the renal dopamine (DA) system. At the high dose there were pronounced increases in urinary DA excretion (> 6000-fold) and renal DA content (> 100-fold); renal NA content doubled. 3. Renal venous DA increased after gludopa infusion, but arterial plasma DA concentrations were not significantly changed. Mean arterial plasma gludopa and L-dopa concentrations reached 890, 3190 ng/mL and 3, 10 ng/mL at low and high doses, respectively. 4. Gludopa resulted in a pronounced dose-dependent fall in renal NA spillover, which at 100 micrograms/kg per min accounted for almost half of the reduction in overall NA spillover rate. 5. The significant falls in renal and extrarenal NA spillover rate during gludopa infusion are consistent with suppression of renal and overall sympathetic activity. Gludopa-induced inhibition of renal NA spillover is likely to be due to the actions of DA generated in the kidney on presynaptic DA-2 and alpha-2 receptors. A central sympathoinhibitory mechanism may explain the reduced total NA spillover.

Effects of enalaprilat on sympathetic activity and metabolism of exercising muscles in rabbit

1. To investigate the effects of angiotensin-converting enzyme inhibition (ACEI) on exercise performance, the following were measured in eight normal rabbits performing graded treadmill exercise during intravenous vehicle saline or enalaprilat infusion: haemodynamics, noradrenaline (NA) spillover, hindlimb oxygen consumption and lactate release. 2. Blood pressure, heart rate (HR), femoral blood flow (FBF), hindlimb lactate release, hindlimb oxygen consumption and hindlimb NA spillover rate were all significantly increased during exercise and the changes during enalaprilat infusion were similar to control responses. 3. At submaximal exercise (6 m/min), ACEI did not significantly alter the responses of hindlimb lactate release, NA spillover rate or oxygen consumption. At the higher exercise load (12 m/min), ACEI reduced hindlimb NA spillover rate (33.1 +/- 4.2 vs 61.3 +/- 17.1 ng/min) and significantly increased oxygen consumption (241 +/- 53.4 vs 133 +/- 23.3%, P < 0.05). The ratio of hindlimb NA spillover rate to total NA spillover rate was markedly increased during exercise, with similar changes being observed in ACEI and control experiments. 4. This study indicates that acute ACEI has a favourable effect on oxygen utilization in exercising muscle in the normal rabbit. Suppression of local sympathetic activation during exercising stress, as reflected in a reduced NA spillover response, may benefit the microcirculation in exercising muscles.

Dependence of the bilayer phase transition temperatures on the structural parameters of phosphatidylcholines

Most saturated diacyl phosphatidylcholines C(X):C(Y)PC (saturated 1,2-diacyl-sn-glycero-3-phosphocholine with X carbons in the sn-1 acyl chain and Y carbons in the sn-2 acyl chain), in excess water, can self-assemble into lamellae which, upon heating, may undergo multiple thermotropic phase transitions at well-defined, discrete temperatures. The transition temperature corresponding to the main or the gel to liquid-crystalline phase transition (Tm) is known for many bilayers of fully hydrated phosphatidylcholines. In this study, we have analyzed the Tm values of 44 molecular species of phosphatidylcholines in terms of their structural and packing characteristics in the gel-state bilayer. Two general equations are thus derived: Tm = 162.26-3651.71 (1/N) - 88.42 (delta C/N) for C(X):C(Y)PC with X > or = Y, and Tm = 157.68-3525.44 (1/N) - 93.28 (delta C/N) for C(X):C(Y)PC with X < Y. Here, N is the minimal hydrophobic thickness of the dimeric C(X):C(Y)PC in the gel-state bilayer and delta C is the effective chain length difference between the sn-1 and sn-2 acyl chains for the monomeric C(X):C(Y)PC in the gel-state bilayer. The advantage of these two equations in predicting the Tm values for phosphatidylcholines with delta C/CL values in the range of 0.07 to 0.40 is their simplicity. A figure containing a total of 173 calculated Tm values is also presented.

Antitumor agents. 126. Novel 4 beta-substituted anilino derivatives of 3',4'-O,O-didemethylpodophyllotoxin as potent inhibitors of human DNA topoisomerase II

A series of derivatives of 3',4'-O,O-didemethylpodophyllotoxin have been synthesized and evaluated for their inhibitor activity against neoplastic cell growth (KB) and against human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. The results show that the compounds possessing a 4 beta-anilino moiety either unsubstituted or substituted at the para (F, COOCH3, COCH3, CN, CH2CN, NO2) or meta (OH) positions or with an ethylenedioxy moiety showed the same or greater activity than etoposide in causing cellular protein-linked DNA breakage and in inhibiting DNA topoisomerase II. However, compared to the corresponding 4'-O-demethyl analogues, the 3',4'-O,O-didemethyl compounds have a similar potency in inhibition of DNA topoisomerase II but are less active in causing cellular protein-linked DNA breakage. Complete correlation between the three biological activities--cytotoxicity, inhibition of DNA topoisomerase II, and induction of protein-linked DNA breakage--was also not observed. This supports the possibility that the biological determinants of action among these compounds may be different.

Real-time color image correlation with a color liquid-crystal television and a Fresnel holographic filter

Incoherent color image correlation with a multiwavelength Fresnel holographic filter and a color liquid-crystal television as a real-time input device is demonstrated.

Calorimetric studies of fully hydrated phosphatidylcholines with highly asymmetric acyl chains

We have semi-synthesized 52 molecular species of saturated diacyl mixed-chain phosphatidylcholines. All 52 phosphatidylcholine molecules are highly asymmetrical with delta C/CL values in the range of 0.43-0.63. The aqueous dispersions of these phosphatidylcholines have been studied by the high-resolution differential scanning calorimetric (DSC) technique. Upon heating, the lipid dispersions prepared individually from these 52 phosphatidylcholines all exhibit a sharp, single, endothermic peak at a characteristic temperature or Tm, implying that the self-assembled lipid molecules in excess water undergo the mixed interdigitated gel to the liquid-crystalline phase transition. The Tm values obtained from aqueous lipid dispersions prepared from these mixed-chain phospholipids have been analyzed based on the molecular packing model of the mixed interdigitated bilayer, and a linear relationship between the Tm and (delta C)-1 for various phospholipids at a constant value of delta is observed. Based on these linear relationships, empirical equations are derived to predict the Tm values for highly asymmetrical mixed-chain phosphatidylcholines with delta C/CL values in the range of 0.43-0.63. The predictive power of these empirical equations is shown to be very good, since a comparison between the predicted and the experimental data indicates that the largest relative error in Kelvin is only 0.4%. A table containing 81 predicted Tm values for highly asymmetrical mixed-chain phosphatidylcholines is presented. The definitions of the various structural parameters such as delta C, CL, delta C/CL and delta are given in the text.

Antitumor agents. 125. New 4 beta-benzoylamino derivatives of 4'-O-demethyl-4-desoxypodophyllotoxin and 4 beta-benzoyl derivatives of 4'-O-demethylpodophyllotoxin as potent inhibitors of human DNA topoisomerase II

A series of 4 beta-benzoylamino (5-17) derivatives of 4'-O-dimethyl-4- desoxypodophyllotoxin and 4 beta-benzoyl (18-20) derivatives of 4'-O-demethyl podophyllotoxin have been synthesized and evaluated for their inhibitory activity against the human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. Compounds 5-13 and 15-17 are more potent than etoposide in causing DNA breakage, while compounds 9, 10, 13, 14, 16, and 20 are more active than etoposide in their inhibition of the human DNA topoisomerase II. The order for the enzyme inhibitory activity of the derivatives of 4'-O-demethyl-4-desoxypodophyllotoxin is 4 beta-arylamino > 4 beta-benzylamino > 4 beta-benzoylamino.

Optical pattern recognition using a synthetic discriminant amplitude-compensated matched filter

A technique for optical pattern recognition using an amplitude-compensated matched filter is presented. With the synthetic discriminant function in a matched spatial filtering application an iterative technique is employed to first obtain the synthetic discriminant functions for the phase-only matched filter and then is extended to the amplitude-compensated matched filter. Computer simulation shows that the suggested spatial filter has a high signal-to-noise ratio and good Horner efficiency, and it is more sensitive to changes in the input image.

Synthesis of new amino acid and peptide derivatives of estradiol and their binding affinities for the estrogen receptor

A series of amino acid and peptide derivatives of estradiol have been synthesized by coupling 17 beta-aminoestra-1,3,5(10)-trien-3-ol, 17-hydrazonoestra-1,3,5(10)-trien-3-ol with amino acids or peptides, using tetrahydrothiazole-2-thione, N-hydroxy-1,4-epoxycyclohex-5-ene-2,3-dicarbonylimide, benzotriazolyloxy-tris(dimethylamino)phosphonium hexafluorophosphate, and p-nitrophenol as reagents. N-protected peptidyl steroids were deprotected by traditional methods. The relative binding affinities of the deprotected derivatives to the estrogen receptor were determined by competitive radioligand binding assay.

[Effect of endometriosis pill No. 2 on beta-endorphin and dynorphin in endometriosis]

In order to explore the correlation between endometriosis and beta-Endorphin, Dynorphin, the beta-Endorphin and Dynorphin levels in menstrual blood of normal women and patients with endometriosis, and the pituitary-hypothalamic beta-Endorphin and Dynorphin levels in animal models were determined. The results indicated: (1) The plasma beta-Endorphin and Dynorphin levels in patients with endometriosis were significantly lower than those in normal women (P < 0.05); the plasma beta-Endorphin levels in patients with endometriosis were significantly higher after treatment of Endometriosis Pill No. 2 (P < 0.05). (2) The pituitary and hypothalamic beta-Endorphin levels in untreated group were significantly higher than those in the control group (P < 0.05); the hypothalamic beta-Endorphin in treated group were obviously higher than those in untreated group (108.35 +/- 35.38 and 66.63 +/- 14.29 respectively). The above-mentioned results presented evidence that the low beta-Endorphin and Dynorphin levels in endometriotic patients play a role in dysmenorrhea; the effect of Endometriosis Pill No. 2 in relieving dysmenorrhea was realized through an increase of plasma and hypothalamic beta-Endorphin levels. (3) The Pituitary and hypothalamic beta-Endorphin levels were significantly different between the animal models of endometriosis and normal control groups.

Bone and haematopoietic defects in mice lacking c-fos

The proto-oncogene c-fos is the cellular homologue of v-fos originally isolated from murine osteosarcoma. Fos protein is a major component of the AP-1 transcription factor complex, which includes members of the jun family. Stable expression of c-fos in mice has been demonstrated in developing bones and teeth, haematopoietic cells, germ cells and in the central nervous system. It has been proposed that c-fos has an important role in signal transduction, cell proliferation and differentiation. We have previously demonstrated that overexpression of c-fos in transgenic and chimaeric mice specifically affects bone, cartilage and haematopoietic cell development. To understand better the function of c-fos in vivo, we used gene targeting in embryonic stem cells to generate cells and mice lacking c-fos. Here we report that heterozygous fos +/- mice appear normal, although females exhibit a distorted transmission frequency. All homozygous fos -/- mice are growth-retarded, develop osteopetrosis with deficiencies in bone remodelling and tooth eruption, and have altered haematopoiesis. These data define the c-Fos protein as an essential molecule for the development of specific cellular compartments.

A stimulatory Mls-1 superantigen is destroyed by ultraviolet light while other Mtv-7 antigens remain intact. Significance for Mls-1 unresponsiveness

Accessory cells present Ag together with costimulatory signals as immunogens and without costimulatory signals as tolerogens. Responsiveness and unresponsiveness are thus alternatives of T cell immune reactions to Ag. Superantigens appear to make an exception; being presented by accessory cells capable of providing costimulatory signals, these Ag induce a strong T cell response but leave T cells unresponsive to a secondary challenge (anergy). We show here that T cell anergy is not a mandatory consequence of superantigen-induced activation. Mls-1- BALB/c recipients of DBA/2 spleen cells mount vigorous Mls-1 responses in vivo but their T cells retain the ability to respond to a subsequent Mls-1 challenge in vitro. We tested the possibility that the inability of DBA/2 spleen cells to inactivate Mls-1-reactive BALB/c T cells was the result of excessive costimulatory activity provided by Mls-1+ DBA/2 B cells. Costimulatory accessory cell activity has been reported to be destroyed by UV light. We exposed superantigen-presenting cells to UV radiation and found that they had lost the ability to stimulate an Mls-1 response without, however, gaining the capacity to render Mls-1-specific T cells anergic. Despite their inability to noticeably stimulate Mls-1-reactive T cells, UV-treated Mls-1+ lymphocytes induced an absolute unresponsiveness in Mls-1- recipients to a second challenge with the superantigen. Our data are in agreement with previous evidence, confirmed here, that BALB/c mice establish immunity against Mls-1+ cells, which causes the accelerated rejection of superantigen-bearing lymphocytes. Thus, our data imply that, whereas it takes stimulatory superantigenic Mtv-7 gene products to induce the activation of superantigen-reactive T cells, nonsuperantigenic Mtv-7 gene products may induce an immune response leading to the elimination of Mtv-7+ lymphoid cells.

A stimulatory Mls-1 superantigen is destroyed by ultraviolet light while other Mtv-7 antigens remain intact. Significance for Mls-1 unresponsiveness

Accessory cells present Ag together with costimulatory signals as immunogens and without costimulatory signals as tolerogens. Responsiveness and unresponsiveness are thus alternatives of T cell immune reactions to Ag. Superantigens appear to make an exception; being presented by accessory cells capable of providing costimulatory signals, these Ag induce a strong T cell response but leave T cells unresponsive to a secondary challenge (anergy). We show here that T cell anergy is not a mandatory consequence of superantigen-induced activation. Mls-1- BALB/c recipients of DBA/2 spleen cells mount vigorous Mls-1 responses in vivo but their T cells retain the ability to respond to a subsequent Mls-1 challenge in vitro. We tested the possibility that the inability of DBA/2 spleen cells to inactivate Mls-1-reactive BALB/c T cells was the result of excessive costimulatory activity provided by Mls-1+ DBA/2 B cells. Costimulatory accessory cell activity has been reported to be destroyed by UV light. We exposed superantigen-presenting cells to UV radiation and found that they had lost the ability to stimulate an Mls-1 response without, however, gaining the capacity to render Mls-1-specific T cells anergic. Despite their inability to noticeably stimulate Mls-1-reactive T cells, UV-treated Mls-1+ lymphocytes induced an absolute unresponsiveness in Mls-1- recipients to a second challenge with the superantigen. Our data are in agreement with previous evidence, confirmed here, that BALB/c mice establish immunity against Mls-1+ cells, which causes the accelerated rejection of superantigen-bearing lymphocytes. Thus, our data imply that, whereas it takes stimulatory superantigenic Mtv-7 gene products to induce the activation of superantigen-reactive T cells, nonsuperantigenic Mtv-7 gene products may induce an immune response leading to the elimination of Mtv-7+ lymphoid cells.

Prospective double-blind study of CEE3 in peri- and postmenopausal women: effects on bone loss and lipoprotein lipids

A prospective double-blind study was carried out in 136 women 0.5 to 21 years since menopause (YSM) in order to demonstrate the effects of a long-acting estriol derivative-Nylestriol (CEE3) on bone loss and lipoprotein lipids. They were orally administered at 2 mg of CEE3 or placebo every 2 weeks. Among 90 subjects who finished 1 year of medication, 49 received CEE3 and 41 placebo. The results were: 1. Serum ALP, Ca/Cr and Hop/Cr in fasting urine decreased in 3 months (P < 0.05); 2. Menopause-related reduction of forearm bone density was restrained; 3. LDL-C decreased in 3 months and HDL-C increased in 6 months (P < 0.05), with no significant changes in TC and TG; 4. Side effects were mild. 1/3 of those with intact uterus had spotting and another 1/3 had moderate withdrawal bleeding after the addition of medroxyprogesterone acetate at the end of 12 months of CEE3 therapy. This study demonstrates that CEE3 is effective and acceptable for preventing osteoporosis and lipoprotein lipids disorder in postmenopausal women. Long-term application awaits further studies.

Biochemistry of the renal V-ATPase

In most eukaryotic cells, vacuolar H(+)-ATPases (V-ATPases) are present primarily or exclusively in intracellular membrane compartments, functioning in the acidification of the endocytic and secretory vacuolar apparatus necessary for constitutive cell function. V-ATPases also participate in renal hydrogen ion secretion in both the proximal and distal nephron, residing at high concentrations on the plasma membrane, where they are regulated physiologically to maintain the acid-base balance of the organism. Recent experiments have begun to reveal how the kidney controls transcellular proton transport while still maintaining acidification of intracellular compartments. Control may occur by recruitment of proton pumps to or away from the plasma membrane. The proton-transporting plasma membrane of intercalated cells is a specialized apparatus that translocates the enzyme between an intracellular membrane pool and the plasma membrane in response to physiological stimuli. Regulation may also occur by changes in the kinetics of the V-ATPase. V-ATPases are a family of structurally similar enzymes which differ in the composition of specific subunits. Cytosolic regulatory enzymes present in renal cells may preferentially affect V-ATPases in selective membrane compartments.

[Treatment of severe viral hepatitis]

Combined treatment of thymosin, amino acid, blood products and glucagon-insulin (G-I) for severe viral hepatitis reduced the death rate to 42.11-54.54% in the years from 1983 to 1985. Since 1986, 207 patients with severe viral hepatitis have been treated in our department, 80 of them died (38.6%). All of the patients were divided into 6 groups receiving different therapeutic measures. Group 1 and 2 received different combinations of the above-mentioned drugs; group 3,4,5 and 6 were given fetal liver cell suspension, hepatocyte growth factor (HGF), Chinese traditional medicine and prostaglandin E1 (PGE1) either alone or in combination with other medications. Therapeutic results were better in group 3,4,5 and 6 than in group 1 and 2. Determination of the activity of tumor necrosis factor (TNF) showed that it was higher in the patients than in the control subjects. TNF activity was increased in rats with experimental liver failure; HGF and PGE1 can protect experimental liver necrosis and reduce the serum TNF activity.

[Combined therapy of brain metastasis in lung cancer]

68 cases of brain metastasis in lung cancer were treated from June 1987 to Dec. 1990. They were randomly divided into 2 groups. The first group was solely treated by radiotherapy and the second one, by radiotherapy adding with the intravenous injection of the 10% Brucea javanica emulsion. The results showed that the living quality and the prolonged median survival of the patients in the second group (15 months) were much better than those in the first group (10 months). The 10% Brucea javanica emulsion has synergetic with radiotherapy in treating brain metastasis in lung cancer.

Expression of vacuolar H(+)-ATPase in mouse osteoclasts during in vitro differentiation

Osteoclasts express high levels of a vacuolar H(+)-adenosinetriphosphatase (H(+)-ATPase) on the ruffled membrane which they employ to dissolve bone mineral by acidifying their site of attachment on bone. The factors that control amplification of H(+)-ATPase during osteoclast differentiation are poorly understood. We examined the expression of vacuolar H(+)-ATPase in a cell culture system in which mouse spleen cells can be induced to differentiate into osteoclasts by coculture with a mouse bone marrow stromal cell line. We found that the coculture system produced active osteoclasts, identified as multinucleated cells with staining for tartrate-resistant acid phosphatase activity that formed genuine resorption pits in bone. These cells developed high levels of H(+)-ATPase expression in culture, and omission of dexamethasone or 1 alpha,25-dihydroxyvitamin D3 from the coculture system each partially suppressed the expression of H(+)-ATPase. The results demonstrate that the spleen and PA6 cell coculture system may be useful for investigating the factors that control the induction of H(+)-ATPase amplification that occurs during osteoclast differentiation.

A cytosolic inhibitor of vacuolar H(+)-ATPases from mammalian kidney

Regulation of the vacuolar H(+)-ATPase in organellar and transepithelial acidification has been attributed to the effects of the proton electrochemical gradient across the membrane or to changes in the number of proton pumps. We now report the identification and purification of a protein from bovine kidney cytosol that inhibits both ATPase activity and proton translocating activity of vacuolar H(+)-ATPases. Its relative molecular weight (M(r)) is 6300, similar to that for protein inhibitors of the mitochondrial F0F1-ATPase. The newly identified cytosolic inhibitor protein may participate in the physiologic regulation of the vacuolar H(+)-ATPase by suppressing activity directly.

Identification and partial purification of a cytosolic activator of vacuolar H(+)-ATPases from mammalian kidney

A factor that activates affinity-purified vacuolar H(+)-ATPase from bovine kidney microsomes was identified and partially purified from bovine kidney cytosol. The activator is a heat-stable, trypsin-sensitive acidic protein with a Mr by gel filtration of approximately 35,000. The activator increased the activity of renal microsomal and brush border H(+)-ATPase by over 60% but stimulated lysosomal H(+)-ATPase activity by only 28%; it had little or no activity against the remaining N-ethylmaleimide-insensitive ATPase in kidney microsomes and other transport ATPases. Stimulation of ATPase activity appeared to result from binding of the activator to the H(+)-ATPase. Activation was saturable, with a Hill coefficient of 1 at low protein concentrations. Both activator binding and stimulation of H(+)-ATPase activity were enhanced at pH values less than or equal to 6.5. The activator has selective effects on different H(+)-ATPases and is poised to activate the enzyme at low physiologic values of cytosolic pH; this newly identified cytosolic proteins may participate in the physiologic regulation of the vacuolar H(+)-ATPase.

Immunologic evidence that vacuolar H+ ATPases with heterogeneous forms of Mr = 31,000 subunit have different membrane distributions in mammalian kidney

Vacuolar H+ ATPases reside in the plasma membrane of several segments of the mammalian nephron. In the proximal tubule, H+ ATPase is located in both the brush-border microvilli and in subvillar invaginations, while in the collecting duct intercalated cells, it is primarily in plasmalemma-associated membranes. H+ ATPase isolated from bovine kidney brush border has a cluster of polypeptides of Mr greater than 31,000 found associated with the Mr = 31,000 subunit, whereas H+ ATPase isolated from microsomes dose not have the additional associated polypeptides (Wang, Z.-Q., and Gluck, S. (1990) J. Biol. Chem. 265, 21957-21965, 1990). In this study, we describe the production of several new monoclonal antibodies to the bovine vacuolar H+ ATPase Mr = 31,000 subunit. Two of the antibodies differed in reactivity to the cluster of Mr greater than 31,000 subunits found in purified bovine kidney brush-border H+ ATPase. Antibody E11 reacted with both the Mr = 31,000 and Mr greater than 31,000 subunits and stained renal brush border intensely. Antibody H8 did not react with the Mr greater than 31,000 polypeptides and did not stain brush border. The heterogeneity of the Mr greater than 31,000 subunits did not appear attributable to glycosylation or phosphorylation. These findings provide further evidence for heterogeneity of the Mr = 31,000 subunit in different renal membrane compartments and suggest a role for the Mr greater than 31,000 polypeptides specific to the brush-border microvilli.

DA-1 receptors mediate renal effects of the dopamine prodrug, gludopa, in conscious rabbits

1. Eight male rabbits were implanted with Doppler flow probes around the lower abdominal aorta and left renal artery. A 2 week recovery period was allowed prior to the experiment. 2. Normal saline, gludopa at 25 micrograms/kg per min and at 100 micrograms/kg per min were each infused i.v. for 60 min. One week later the same protocol was administered to four of these animals in addition to DA-1 antagonist SCH 23390 (0.3 mg/kg i.v.) before gludopa infusion. 3. Gludopa elicited significant increases in urine flow, urinary sodium excretion and renal blood flow, and decreased renal vascular resistance. These changes were abolished by the DA-1 antagonist. Blood pressure, heart rate and hindlimb blood flow remained unchanged. 4. Urine dopamine excretion was increased 1200-fold and 7800-fold after gludopa administration at 25 micrograms/kg per min and 100 micrograms/kg per min, respectively, while plasma dopamine concentration and plasma renin activity (PRA) were not significantly altered. However, PRA was elevated by gludopa with DA-1 antagonism. 5. The renal vasodilation, natriuresis and diuresis produced by gludopa in conscious rabbits appears to be mediated by locally generated dopamine via DA-1 receptors.

Antitumor agents. 124. New 4 beta-substituted aniline derivatives of 6,7-O,O-demethylene-4'-O-demethylpodophyllotoxin and related compounds as potent inhibitors of human DNA topoisomerase II

A series of 6,7-O,O-demethylene-4'-O-demethyl-4 beta-(substituted anilino)-4-desoxypodophyllotoxins (18-23), 6,7-O,O-demethylene-6,7-O,O-dimethyl-4'-O-demethyl-4 beta-(substituted anilino)-4-desoxypodophyllotoxins (28-31), and their corresponding 4'-O-methyl analogues (12-17 and 24-27) have been synthesized and evaluated for their inhibitory activity against the human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. Compounds 18-23 are 2-fold more potent than etoposide and compounds 12, 16, 17, 30, and 31 are as active as etoposide in their inhibition of the human DNA topoisomerase II. Compounds 19 and 20 and 29-31 are as active or more active than etoposide in causing protein-linked DNA breakage. These results indicate that a free C-4' hydroxy group is essential for the DNA breakage activity, and that the hydroxyl groups at C-6 and -7 positions may be involved in an interaction which is responsible for the inhibitory activity of DNA topoisomerase II. The maintenance of an intact methylene dioxy-type ring-A system would contribute to enhanced activity. In addition, the sterically less hindered substitution at C-6 and C-7 positions may be important for optimal interactions with DNA topoisomerase II. There is no correlation between the ability of these compounds to inhibit DNA topoisomerase II and their ability to cause protein-linked DNA breaks in cells. This may relate to the difference in uptake of these compounds. The better correlation was observed between the protein-linked DNA breaks and the cytotoxicity in KB cells of these compounds.

Antitumor agents. 123. Synthesis and human DNA topoisomerase II inhibitory activity of 2'-chloro derivatives of etoposide and 4 beta-(arylamino)-4'-O-demethylpodophyllotoxins

The 2'-chloro derivatives of etoposide and 4 beta-(arylamino)-4'-O-demethylpodophyllotoxins have been synthesized and evaluated for their inhibitory activity against the human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. The results showed that none of the compounds are active as a result of the C-2' chloro substitution on ring E. This would suggest that the free rotation of ring E is essential for the aforementioned enzyme inhibitory activity. In addition, these 2'-chloro derivatives showed no significant cytotoxicity (KB).

Antitumor agents. 120. New 4-substituted benzylamine and benzyl ether derivatives of 4'-O-demethylepipodophyllotoxin as potent inhibitors of human DNA topoisomerase II

A number of new 4'-O-demethylepipodophyllotoxin derivatives possessing various 4 beta-N- or 4 beta-O-benzyl groups have been synthesized and evaluated for their inhibitory activity against the human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. The 4 beta-N-benzyl derivatives 9-22 are, in general, as active or more active than etoposide (1). The most active compounds are 14, 16, and 17, which are more than 2-fold more potent than 1. The results indicated that a basic unsubstituted 4 beta-benzylamino moiety is structurally required for the enhanced activity. Replacement of the benzyl nitrogen with oxygen gave compounds (23 and 24) which are inactive. The ability of these compounds to inhibit human DNA topoisomerase II and to cause protein-linked DNA breakage appears to have no direct correlation with cytotoxicity in KB cells.

A novel target cell for c-fos-induced oncogenesis: development of chondrogenic tumours in embryonic stem cell chimeras

Embryonic stem (ES) cells were used to investigate the target cell specificity and consequences of c-fos when expressed ectopically during embryonic development. Chimeric mice generated with different ES cell clones selected for high exogenous c-fos expression were not affected during embryonic development; however, a high frequency of cartilage tumours developed as early as 3-4 weeks of age apparently independent of the extent of chimerism. The tumours originated from cartilagenous tissues and contained many chondrocytes. Expression of exogenous c-fos RNA and Fos protein was observed during development but was highest in tumour tissues, predominantly in differentiating chondrocytes. A number of primary and clonal tumour-derived cell lines were established which expressed high levels of c-fos, c-jun as well as the cartilage-specific gene type II collagen and which gave rise to cartilage tumours in vivo, some of which also contained bone. Interestingly, the levels of c-Fos and c-Jun appeared to be coordinately regulated in the cell lines as well as in chimeric tissues. Thus, we demonstrate that chondrogenic cells and earlier progenitors are specially transformed by Fos/Jun and therefore represent a novel mesenchymal target cell for c-fos overexpression.

[Treatment of endometriosis with removing blood stasis and purgation method]

According to the method of differentiation of symptom complexes of traditional Chinese medicine (TCM), endometriosis is a disease of blood stasis and mass in the lower portion of abdomen. 76 cases were treated by TCM prescription named endometriotic pill No 1 with rhubarb as the main ingredient. The chief functions of the rhubarb were removing blood stasis, disintegrating mass and purgation. The total effective rate was 80.26%. Among them, the effective rate of dysmenorrhea was 88.89%, that of pelvic pain was 66.72%, that of intercourse pain 72.12%, and diminishing in size of mass or nodule 22.15%; 3 cases of 22 infertility got pregnant (13.63%). The results revealed that the endometriotic pill No 1 yielded distinct improvement in the treatment of endometriosis, including clinical symptoms and signs, laboratory assay of blood rheology, serum Ig, subgroup of T lymphocyte (OKT system) and PG.

Determination of furosine in biomedical samples employing an improved hydrolysis and high-performance liquid chromatographic technique

Traditionally, the most sensitive and specific determination of non-enzymatic protein glycation has involved an 18-24-h acid hydrolysis in order to generate the compound furosine, which has been detected employing reversed-phase h.p.l.c. In this study, we have reported that significant quantities of furosine can be generated with much shorter hydrolysis times employing a 90-min vapor-phase acid hydrolysis procedure. The furosine generated by vapor-phase hydrolysis is then quantitated by pulsed amperometric detection using anion-exchange high-performance liquid chromatography. Employing this method, we were able to show that furosine generated from acid hydrolysis of purified hepatic membranes in a diabetic and non-diabetic animal model agreed with traditional methods assessing total glycated protein (i.e., boronate affinity methods).

The influence of acyl chain-length asymmetry on the phase transition parameters of phosphatidylcholine dispersions

The influence of acyl chain-length asymmetry on the thermodynamic parameters (Tm, delta H, and delta S) associated with the reversible main phase transition of aqueous dispersions prepared from saturated diacyl phosphatidylcholines was studied by high-resolution differential scanning calorimetry. Two series of saturated diacyl phosphatidylcholines, grouped according to their molecular weights of 678 and 706, with a total number of 25 molecular species were examined. The normalized acyl chain-length difference between the sn-1 and sn-2 acyl chains for a given phospholipid molecule in the gel-state bilayer is expressed quantitatively by the structural parameter delta C/CL, and the values of delta C/CL for the two series of lipids under study vary considerably from 0.04 to 0.67. When the value of delta C/CL is within the range of 0.09-0.40, it was shown that the thermodynamic parameters are, to a first approximation, a linear function of delta C/CL with a negative slope. In addition, the experimental Tm values and the predicted Tm values put forward by Huang (Biochemistry (1991) 30, 26-30) are in very good agreement. Beyond the point of delta C/CL = 0.41, the influence of acyl chain-length asymmetry on the thermodynamic parameters deviates significantly from a linear function. In fact, within the range of delta C/CL values of 0.42-0.67, the thermodynamic parameters in the Tm (or delta H) vs. delta C/CL plot were shown to be bell-shaped with the maximal Tm (or delta H) at delta C/CL = 0.57. These results are discussed in terms of changes in the acyl chain packing modes of various phosphatidylcholine molecules within the gel-state bilayer in excess water.

Thermotropic and mixing behavior of mixed-chain phosphatidylcholines with molecular weights identical with that of L-alpha-dipalmitoylphosphatidylcholine

The thermotropic phase behavior of 10 mixed-chain phosphatidylcholines, in excess water, has been examined and compared with that of identical-chain C(16):C(16)PC by using high-resolution differential scanning calorimetry (DSC). The molecular weights (MW) of these 11 molecular species are the same, but their delta C/CL values, or the normalized chain length differences, vary considerably, ranging from 0.035 to 0.540. The thermodynamic parameters (Tm, delta H, and delta S) associated with the main phase transitions for these lipid dispersions exhibit biphasic V-shaped curves, when plotted against delta C/CL. Similar characteristic curves have been reported previously for aqueous dispersions of mixed-chain phosphatidylcholines with MW identical with that of C(17):C(17)PC [Lin et al. (1990) Biochemistry 29, 7063-7072]. The initial decrease in Tm (delta H or delta S) with increasing values of delta C/CL is attributed to the progressive increase in the magnitude of the chain-terminal perturbations on the conformational statistics of the adjacent hydrocarbon chains and hence the lateral chain-chain interactions of these mixed-chain phosphatidylcholines in the gel-state bilayer. At delta C/CL approximately equal to 0.42, the chain-end perturbation is presumably at its maximum; beyond this point, the highly asymmetric phosphatidylcholines are proposed to pack, at T less than Tm, into the mixed interdigitated bilayer. In this new packing mode, the methyl ends of the longer acyl chains are relocated at the interfaces between the hydrocarbon core of the bilayer and the aqueous medium. This disposition of the bulky chain ends releases a certain degree of chain-chain packing disorders, leading to an increase in Tm (delta H or delta S) with increasing delta C/CL.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of rGM-CSF on leukemia cell proliferation and on the incorporation of cytosine arabinoside into DNA

In vitro studies of the effects of recombinant granulocyte macrophage-colony stimulating factor (rGM-CSF) on freshly obtained human leukemia cells were conducted to determine if there is a relationship between the effects of this growth factor on the proliferative characteristics of leukemia cells and on their incorporation of cytosine arabinoside (araC) into DNA. While rGM-CSF was found to be able to stimulate both leukemia cell proliferation and araC incorporation, for individual leukemia specimens there was no consistent relationship among these effects. In some specimens proliferation was stimulated without an increase in araC incorporation. The reverse was also observed. These studies demonstrate the difficulty in identifying assays capable of predicting the clinical effects of growth factors on leukemia cells in patients since the effect in vitro vary with the assay.

Liver and kidney tissue membranes as tissue markers for nonenzymatic glycosylation

We investigated the relationship of serum protein glycosylation to peripheral tissue membrane glycosylation. We studied 27 Sprague-Dawley rats and induced diabetes in 20 of them. Blood glucose levels were treated in 10 of the diabetic animals with daily subcutaneous insulin. After 8 wk, liver and kidney tissue was removed, purified membranes were prepared, and the percentage of glycosylated membrane protein was determined for the liver and kidney membranes by boronate-affinity methods. The percentage of glycosylated membrane protein for both liver and kidney tissue was found to correlate significantly with the glycemic state of the animal as assessed with glycosylated serum albumin, total glycosylated serum proteins, and glycosylated hemoglobin determinations (P less than 0.001 for each glycosylated protein parameter). In addition, the percentage of glycosylated membrane protein in the liver tissue correlated significantly with the measured level in the corresponding kidney tissue (r = 0.78, P less than 0.001). To identify the nature of the glycosylated membrane proteins, boronate-affinity methods were used to separate the glycosylated and nonglycosylated membrane proteins. It was determined that two major glycosylated protein bands exist for the liver membrane (78,000 and 58,700 Mr) and four for the kidney membranes (ranging from 48,700 to 74,000 Mr). The ultrastructural location and identification of these glycosylated membrane proteins are not known. This study demonstrates that measurement of clinical glycemic state, as reflected in glycosylated blood protein parameters such as glycosylated serum albumin and glycosylated hemoglobin, correlates significantly with ongoing tissue membrane accumulation of glucose.

Localization of regulatory elements controlling human MYCN expression

Expression of the cellular oncogene MYCN is restricted to few cell lineages and is highest during development both in mouse and in humans. In pursuit of elucidating the mechanisms underlying MYCN regulation we introduced a human MYCN clone (pNb-9) with approximately 2.5 kbp 5'- and 6 kbp 3'-flanking genomic sequences into different murine and human cell lines as well as into mice. In all cases we found a correlation between the expression of the exogenous and the endogenous MYCN. Among cell lines, only those expressing the endogenous gene also expressed the transfected gene. In the transgenic mice transcripts of the transgene were present in proportion to the transcripts of the endogenous MYCN gene with the highest level in the brain. Therefore, the genetic information necessary for regulated expression of MYCN appears to be contained in pNb-9. To localize the DNA-regions responsible for regulated expression, we generated MYCN/CAT hybrid genes with different portions of the putative MYCN promoter region linked to the reporter gene. Transient transfections into various murine and human cell lines identified three DNA regions apparently involved in the regulation of expression. One region about 200 bp upstream of the transcriptional start site is responsible for a basal level of MYCN expression. A second region located about 800 bp further upstream appears to be involved in cell type-specific gene activation. The third regulatory element is located at the 3' end of the first exon and/or in the first intron and may mediate tissue-specific down regulation of gene expression.

Effect of 4 beta-arylamino derivatives of 4'-O-demethylepipodophyllotoxin on human DNA topoisomerase II, tubulin polymerization, KB cells, and their resistant variants

Six 4 beta-arylamino derivatives of 4'-O-demethylepipodophyllotoxin were examined for inhibitory activity against human DNA topoisomerase II and tubulin polymerization, their ability to generate protein-linked DNA breaks in cells, and their cytotoxicity toward the KB cell line and its VP-16- and vincristine-resistant variants. Five of these derivatives were 5- to 10-fold more potent than VP-16 as inhibitors of DNA topoisomerase II in vitro, and all of these derivatives could generate the same amount of or more protein-linked DNA breaks in cells than VP-16 at 1-20 microMs. Tubulin polymerization was inhibited by these compounds to different degrees in the order: podophyllotoxin greater than W73 greater than W87 greater than NPF greater than NPC greater than W68 greater than W38 greater than VP-16. These analogues were cytotoxic not only to KB cells but also to their VP-16-resistant and vincristine-resistant variants which showed decreased cellular uptake of VP-16 and a decrease in DNA topoisomerase II content or overexpression of MDR1 phenotype. These characteristics may cause these derivatives to have different spectrums of antitumor activity.

Studies of the proliferation and differentiation of immature myeloid cells in vitro: 4: Preculture proto-oncogene expression and the behaviour of myeloid leukemia cells in vitro

Studies were conducted to determine the relationship between the pretherapy characteristics of leukemia cells and their behaviour during culture in vitro. Leukemia cells which proliferated well in vitro also proliferated well in vivo. Cells which manifested myeloid or monocytic differentiation in vivo tended to manifest differentiation along these lines in vitro. Cells which manifested high levels of expression of c-fms, c-fes, or triose phosphate isomerase prior to culture were likely to differentiate in vitro, with high levels of c-fes expression being related to myeloid maturation. These observations suggest that differentiation at the molecular level prior to culture is a requisite for leukemia cell differentiation in vitro. The same may be true for differentiation in vivo under the influence of exogenously administered agents such as cytotoxic chemotherapy or recombinant growth factors.

Adaptive response to chromosome damage in cultured human lymphocytes primed with low doses of X-rays

Human lymphocytes exposed to 0.02 Gy of X-rays in the G1 but not the G0 phase became less susceptible to the induction of chromosome aberrations of the chromosome type by subsequent exposure to 3 Gy of X-rays. The induction of chromatid-type aberrations was not affected by the pretreatment with the priming dose. The expression of this adaptive-type response was transitory, being maximum at 5 h, and disappeared at 9 h after the initial low-dose exposure. Cell-cycle analysis excluded the possibility of a spurious consequence of differential cell-cycle progression.

Isolation and properties of bovine kidney brush border vacuolar H(+)-ATPase. A proton pump with enzymatic and structural differences from kidney microsomal H(+)-ATPase

Vacuolar H(+)-ATPase was isolated from highly purified bovine kidney brush border, using a previously described immunoaffinity method. The affinity purified enzyme had reconstitutively active ATP-induced acidification that was inhibited by N-ethylmaleimide. The brush border H(+)-ATPase had a single pH optimum of 7.3, and a single Km for ATP of 360 microM. The enzyme showed no lipid activation; it had a substrate preference of ATP greater than ITP greater than UTP greater than GTP much greater than CTP, with an ATP:GTP selectivity of 1.69. The brush border H(+)-ATPase required no monovalent anion or cation for activity and was inhibited by the oxyanions NO3(-1) much greater than SO4(-2); sulfite stimulated activity at low concentrations and inhibited at higher concentrations. The inhibition produced by nitrate could not be attributed to dissociation of subunits from the enzyme. The divalent or trivalent cation preference was Mn+2 much greater than Mg+2 much greater than Co+2 greater than Al+3 greater than Ca+2 much greater than Ba+2,Sr+2; 1 mM Zn+2 inhibited the enzyme completely, but Cu+2 inhibited only 49% of activity at concentrations up to 5 mM. Sodium dodecyl sulfate-polyacrylamide gels of the brush border H(+)-ATPase showed subunits at Mr 70,000, a doublet at 56,000, 45,000, 42,000, 38,000, 33,000, 31,000, 15,000, 14,000, and 12,000. On two-dimensional gels, the pl value for the Mr 70,000 subunit was 6.3, for the Mr 56,000 was 6.4, and for the Mr 31,000 was 7.5-8.5, and microheterogeneity was observed in the Mr 56,000 and 31,000 subunits. A comparison of kidney cortex brush border H(+)-ATPase with kidney cortex microsomal H(+)-ATPase revealed differences in pH optimum, Km for ATP, lipid dependence, substrate preference, divalent ion preference, copper sensitivity, and in microheterogeneity of the Mr 56,000 and 31,000 subunits, providing evidence that different functional and structural classes of vacuolar H(+)-ATPase are segregated to specific membrane compartments.

Nifedipine pharmacodynamics and pharmacokinetics in treatment of congestive heart failure

In 22 of 27 cases of congestive heart failure (CHF) treated with nifedipine (NIF), significant improvements in resting hemodynamics were noticed. The higher the basal systemic vascular resistance (SVR) and pulmonary artery end diastolic pressure (PAEDP), the greater the magnitude of reduction was achieved (r = 0.84 and 0.77, P less than 0.01, respectively). Exercise hemodynamic investigation showed that NIF lowered SVR, PAEDP and pulmonary vascular resistance (PVR), with an increase in stroke volume (SV) at the serum concentration of 5-10 ng/ml. Maximum effect was observed at the concentration of 20 ng/ml. No further vasodilation was attainable with serum concentrations above 20 ng/ml. No remarkable deviation of NIF pharmacokinetic parameters from the normal ranges was found in CHF patients. The plasma norepinephrine level decreased markedly 2 and 7 hours after the use of NIF. It is concluded that oral NIF is beneficial to severe CHF patients with low cardiac output and high SVR.

Simultaneous preparation of paired, syncytial, microvillous and basal membranes from human placenta

A method for the simultaneous preparation of microvillous and basal membrane vesicles from human placental syncytiotrophoblast is described. Mg2(+)-aggregated basal membranes are separated from microvillous membranes by low-speed centrifugation after initial homogenization and centrifugation steps. Microvillous membranes (MVM) are obtained from the low speed supernatant while basal membranes (BM) contained in the Mg2(+)-aggregated material are resuspended and further purified on a sucrose step gradient. MVM and BM prepared by this method were enriched 20-fold and 11-fold as determined by the membrane marker enzymes, alkaline phosphatase (MVM) and adenylate cyclase (BM). There was minimal cross-contamination of the two isolated plasma membrane fractions and the yields obtained were 26% (MVM) and 21% (BM) compared to the initial homogenate. The MVM and BM fractions were free from contamination by mitochondrial or lysosomal membranes and showed only minor contamination by microsomal membranes. The two membrane fractions were also tested for the presence of non-syncytial plasma membranes by electrophoretic immunoblotting. Contamination of both MVM and BM by fibroblast, endothelial, macrophage and cytotrophoblast plasma membranes amounted to less than 15% of the total membrane protein as determined by immunoblotting. Vesicle orientation, determined from the latency of specific concanavalin A binding, was 88 +/- 4% right-side out for MVM and 73 +/- 12% right-side out for BM. This simple preparative procedure produces a high yield of both MVM and BM from human placenta. The analytical data demonstrates that 'paired' MVM and BM fractions derived from the same placental tissue have a high purity in terms not only of contamination by intracellular membranes, but also in terms of contamination by non-syncytial plasma membranes.

Amplitude compensated matched filters using circular harmonic expansion and a Mellin transform

The new techniques of amplitude compensated matched filtering using circular harmonic expansion and a Mellin transform are presented. These techniques yield much better discrimination and sharper autocorrelation peaks compared with the classical matched spatial filtering. Aside from these advantages, the amplitude compensated circular harmonic expansion matched filtering can also yield rotation invariance, and the amplitude compensated Mellin transform matched filtering can yield scale invariance. By computer simulation, we have verified the unique advantages of the new methods. We also provide 3-D graphs of autocorrelation and cross correlation.

Mixing behavior of identical molecular weight phosphatidylcholines with various chain-length differences in two-component lamellae

It has recently been suggested that mixed-chain phosphatidylcholines with normalized chain length differences (deltaC/CL) in the range of 0.10-0.40 undergo spontaneous self-assembly in excess water at T less than Tm into the partially interdigitated bilayer and those with delta C/CL values in the range of 0.44-0.57 form, in excess water, mixed interdigitated bilayers at T less than Tm. The mixing behavior of binary mixtures of C(22):C(12)PC/C(17):C(17)PC, C(22):C(12)/C(15):C(19)PC, and C(15):C(19)PC/C(13):C(21)PC reported in this work is used to support this view. The values of delta C/CL for C(17):C(17)PC, C(15):C(19)PC, C(13):C(21)PC, and C(22):C(12)PC are 0.10, 0.15, 0.35, and 0.55, respectively. The binary mixture of C(15):C(19)PC/C(13):C(21)PC exhibits a lens-shaped phase diagram, indicating that these two identical molecular weight (MW) lipids with delta C/CL values less than 0.4 are completely miscible over the entire compositional range in both gel and liquid-crystalline phases. In contrast, the phase diagrams of C(22):C(12)PC/C(17):C(17)PC and C(22):C(12)PC/C(15):C(19)PC are eutectic, indicating immiscibility of the component lipids over a wide compositional range in the gel phase. This immiscibility of identical MW lipids in the bilayer plane can be attributed to the different packing properties of the component lipids in the bilayer at T less than Tm.

Strain difference in pulmonary vascular responsiveness to hypoxia in rats

The difference in pulmonary vascular response to hypoxia between Hilltop Sprague-Dawley (HT) rats and Wistar (W) rats was studied. Effects of inhibitor of leukotriene (LT) synthesis or prostaglandin (PG) synthesis on hypoxic pulmonary vasoconstriction (HPV) and chronic pulmonary hypertension were observed, and variations in plasma TXB2 and 6-keto-PGF1 alpha during hypoxia were determined. The results showed that in rats of both strains LTs are the major mediator of HPV, which is also mediated by vasoconstrictive PGs in HT rats, while modulated by vasodilative PGs in W rats. This might be the crucial mechanism responsible for the higher pulmonary vascular responsiveness in HT rats. Differences in the modulating effect of histamine and in the structural feature of pulmonary arteriole might be contributing factors as well.

Antitumor agents. 113. New 4 beta-arylamino derivatives of 4'-O-demethylepipodophyllotoxin and related compounds as potent inhibitors of human DNA topoisomerase II

A number of 4'-O-demethylepipodophyllotoxin derivatives possessing various 4 beta-N-, 4 beta-O- or 4 beta-S-aromatic rings have been synthesized and evaluated for their inhibitory activity against the human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. The results indicated, that for DNA topoisomerase II, a basic unsubstituted 4 beta-anilino moiety is structurally required for the enhanced activity. Substitution on this moiety with CN, COOCH3, COOC2H5, OH and COOCH3, OCH3, COCH3, CH2OH, OCH2O, OCH2CH2O, phenoxy, morpholino, NO2, and NH2 either at the para and/or the meta position yielded compounds which are as potent or more potent than etoposide. Substitution with COOC2H5 and OH at the ortho position afforded inactive compounds. Replacement of the aryl nitrogen with oxygen or sulfur gave compounds which are much less active or inactive. However, replacement of the phenyl ring with a pyridine nucleus furnished compounds which are as active or slightly more active than etoposide. There is a lack of correlation between the ability of these compounds in inhibiting DNA topoisomerase II and in causing protein-linked DNA breaks.