Relationship of 133Xe cerebral blood flow to middle cerebral arterial flow velocity in men at rest

Cerebral blood flow (CBF) was measured by 133Xe clearance simultaneously with the velocity of blood flow through the left middle cerebral artery (MCA) over a wide range of arterial PCO2 in eight normal men. Average arterial PCO2, which was varied by giving 4% and 6% CO2 in O2 and by controlled hyperventilation on O2, ranged from 25.3 to 49.9 mm Hg. Corresponding average values of global CBF15 were 27.2 and 65.0 ml 100 g min-1, respectively, whereas MCA blood-flow velocity ranged from 42.8 to 94.2 cm/s. The relationship of CBF to MCA blood-flow velocity over the imposed range of arterial PCO2 was described analytically by a parabola with the equation: CBF = 22.8 - 0.17 x velocity + 0.006 x velocity2 The observed data indicate that MCA blood-flow velocity is a useful index of CBF response to change in arterial PCO2 during O2 breathing at rest. With respect to baseline values measured while breathing 100% O2 spontaneously, percent changes in velocity were significantly smaller than corresponding percent changes in CBF at increased levels of arterial PCO2 and larger than CBF changes at the lower arterial PCO2. These observed relative changes are consistent with MCA vasodilation at the site of measurement during exposure to progressive hypercapnia and also during extreme hyperventilation hypocapnia.

Dynamic fluorescence changes during photodynamic therapy in vivo and in vitro of hydrophilic A1(III) phthalocyanine tetrasulphonate and lipophilic Zn(II) phthalocyanine administered in liposomes

The fluorescence emission of hydrophilic tetrasulphonated aluminium phthalocyanine (AlPcS4) and hydrophobic zinc phthalocyanine (ZnPc), bound to the membrane of liposomes, was investigated in vivo in an appropriate tumour model of the rat bladder and in RR 1022 epithelial cells of the rat. The sensitizers were administered systemically to the rats and photodynamic therapy (PDT) was performed 24 h later. During PDT treatment, the fluorescence was measured every 30 s. The fluorescence was excited with 633 nm light from an HeNe laser and the fluorescence spectra were detected with an optical multichannel analyser system. PDT was performed for both sensitizers using 672 nm light from an Ar+ dye laser. The fluorescence changes during PDT were significantly different for the two phthalocyanines. For AlPcS4, an initial fluorescence intensity increase, followed by subsequent photobleaching, was observed. In contrast, ZnPc fluorescence showed an exponential decrease and no increase at the start of treatment. Tumour necrosis 24 h after PDT was significant only for ZnPc. RR 1022 cells incubated for 24 h with AlPcS4 revealed a granular fluorescence pattern, whereas ZnPc was localized diffusely in the cytoplasm of the cells. In agreement with the in vivo measurements, subcellular relocalization and a fluorescence intensity increase were detected exclusively in the case of AlPcS4. Morphological changes at this time were significant only for ZnPc. The subcellular localization and fluorescence kinetics were obtained using a confocal laser scanning microscope.

Characterization of an IL-6-like molecule from an echinoderm (Asterias forbesi)

Our previous studies have demonstrated the presence of two of the three vertebrate inflammatory cytokines in invertebrates, namely, interleukin (IL)-1 and tumour necrosis factor (TNF). We studied the coelomic fluid of the echinoderm, Asterias forbesi, to determine whether it contained the third inflammatory cytokine, IL-6. Coelomic fluids were concentrated and then fractionated by a combination of gel sieve chromatography and preparative isoelectric focusing. The M, observed for the invertebrate IL-6-like molecule was approximately 30,000 and the pI was 5.5. Western blot analysis using a polyclonal rabbit antiserum to human IL-6 detected a band at approximately 30,000 Da. The invertebrate IL-6 was inhibited by an antiserum to human IL-6 when used in the B9 assay. Finally, the coelomocytes were found to be capable or releasing the IL-6-like molecule as early as 12 h following stimulation by LPS. These results, together with our other data, show that echinoderms possess correlates of all three vertebrate inflammatory cytokines.

Comparison of endothelin B (ETB) receptors in rabbit isolated pulmonary artery and bronchus

1. To explore potential differences between endothelin (ET) receptors in airway versus vascular smooth muscle from the same species, the ETB receptors mediating contractions produced by ET-1, ET-3 and the selective ETB ligands, sarafotoxin S6c (S6c) and BQ-3020, in rabbit bronchus and pulmonary artery were investigated by use of peptide and non-peptide ET receptor antagonists. 2. In rabbit pulmonary artery SB 209670 (10 microM), a mixed ETA/ETB receptor antagonist, was a more potent antagonist of contractions produced by S6c (pKB = 7.7; n = 9; P < 0.05), than those elicited by ET-1 (pKB = 6.7; n = 6) or ET-3 (pKB = 6.7; n = 5). BQ-788 (10 microM), an ETB receptor antagonist, inhibited responses produced by ET-3 (pKB = 5.1; n = 8), BQ-3020 (pKB = 5.2; n = 4) or S6c (pKB = 6.2; n = 9; P < 0.05 compared to potency versus ET-3- or BQ-3020-induced contractions), but was without inhibitory effect on ET-1-induced contractions (n = 5). RES-701 (10 microM), another selective ETB receptor antagonist, was without effect on contractions produced by S6c (n = 4) or ET-1 (n = 4), and potentiated ET-3- (n = 5) or BQ-3020-induced responses (n = 4). 3. The combination of BQ-788 (10 microM) and BQ-123 (10 microM), an ETA-selective receptor antagonist, antagonized contractions produced by lower concentrations of ET-1 (1 and 3 nM) in rabbit pulmonary artery, but was without effect on responses elicited by higher concentrations of ET-1 (n = 5). The combination of RES-701 (10 microM) and BQ-123 (10 microM) potentiated responses elicited by ET-1, producing a 3.7 fold shift to the left in the agonist concentration-response curve (n = 5). 4. In rabbit bronchus SB 209670 (3 microM) had similar potency for antagonism of contractions produced by ET-1 (pKB = 6.3; n = 6), ET-3 (pKB = 6.5; n = 6) or S6c (pKB = 6.1; n = 8). BQ-788 (3 microM) was without effect on responses elicited by ET-1, ET-3 or S6c (n = 6) but antagonized BQ-3020-induced contractions (pKB = 6.4; n = 4). RES-701 (3 microM) was without effect on contractions produced by S6c (n = 6) or BQ-3020 (n = 4), and potentiated rather than antagonized ET-1- or ET-3-induced responses (n = 6), reflected by a significant (about 6 fold) shift to the left in ET-1 or ET-3 concentration-response curves. The combination of BQ-788 (3 microM) and BQ-123 (3 microM) was without effect on contractions produced by ET-1 in rabbit bronchus (n = 6). The combination of RES-701 (3 microM) and BQ-123 (3 microM) potentiated responses elicited by ET-1, producing a 5.2 fold shift to the left in the agonist concentration-response curve (n = 5). 5. BQ-123 (3 or 10 microM), an ETA-selective receptor antagonist, was without effect on ET-1, ET-3 or S6c concentration-response curves (n = 3-6) in rabbit pulmonary artery or rabbit bronchus. 6. These data indicate that contractions induced by ET-1, ET-3, S6c and BQ-3020 in rabbit pulmonary artery or rabbit bronchus appear to be mediated predominantly via stimulation of ETB receptors. However, the qualitative and quantitative differences in the relative profiles of the various structurally diverse peptide and non-peptide antagonists examined suggests that responses produced by the ET ligands may not be mediated by a homogeneous ETB receptor population. In addition, the results suggest that differences exist in the ETB receptors mediating contraction in pulmonary vascular versus airway tissues in the same species. These receptors are not very sensitive to the standard ETB receptor antagonists, BQ-788 and RES-701. Furthermore, the results also provide further evidence that the potencies of ET receptor antagonists depend upon the ET agonist.

Characterization of a defense complex consisting of interleukin 1 and phenol oxidase from the hemolymph of the tobacco hornworm, Manduca sexta

Hemolymph of fifth instar Manduca sexta larvae collected under non-sterile conditions exhibited the presence of a novel high molecular weight protein complex, which was absent from the hemolymph collected aseptically. The high molecular weight complex consisted of, at least prophenol oxidase, phenol oxidase, and an interleukin 1-like molecule, thereby demonstrating the generation of this complex as a consequence of a host defense response. While the native phenol oxidase and the interleukin 1-like molecule possessed molecular weights of about 80,000 and 17,000, respectively, the complex had a molecular weight of about 400,000. Apart from prophenol oxidase, phenol oxidase, and interleukin 1, dopachrome isomerase and other, as of yet unidentified, proteins may be part of the complex as judged by the presence of additional bands observed during SDS-polyacrylamide gel electrophoresis. The significance of the assembly of this defense complex for insect host defense strategies is discussed.

Spinal endothelin content is elevated after moderate local trauma in the rat to levels associated with locomotor dysfunction after intrathecal injection

The role of endothelin (ET) in the pathophysiology of secondary neural damage after experimental spinal cord injury (SCI) was examined in a rat model of weight-drop contusion injury. Initial studies demonstrated a significant increase in spinal ET concentrations in a 7.5-mm segment of tissue (centered at the impact site) at 30 min, 4 h, and 24 h after a moderate (50 g-cm) contusion injury. Subsequent experiments were aimed at reproducing these elevations by the intrathecal (i.t.) administration of ET and observing the effect on locomotor function. These studies showed that i.t. dosage of 9.6 ng produced spinal cord elevations of ET similar to those seen 30 min after moderate SCI as well as mild locomotor deficits. A 48 ng dose of ET resulted in moderate to severe locomotor deficits that were associated with spinal ET elevations much greater than those seen after injury. The mild deficits attributable to the lower dose of ET could contribute to the pathophysiological actions of other purported secondary injury mediators. The more pronounced locomotor deficits associated with the higher dose could be of relevance for severe SCI.

Nonpeptide endothelin receptor antagonists. VI: Pharmacological characterization of SB 217242, a potent and highly bioavailable endothelin receptor antagonist

This study describes the pharmacological characterization of SB 217242, a highly potent orally bioavailable nonpeptide antagonist of both endothelin type A (ETA) and endothelin type B (ETB) receptors. In human cloned ETA and ETB receptors, SB 217242 produced concentration-dependent displacement of [125]I-endothelin-1 (ET-1) in both receptor subtypes with Ki values of 1.1 and 111 nM, respectively. SB 217242 produced concentration-dependent, parallel rightward shifts in the ET-1 concentration-response curves in rat isolated aorta and human isolated pulmonary artery (ETA receptor-mediated vascular contraction) with Kb values of 4.4 and 5.0 nM, respectively. SB 217242 was 4-, 62- and 125-fold more potent as an ETA receptor antagonist than the previously reported compounds BQ-123, PD 142893 and Ro 46-2005, respectively. SB 217242 (10 microM) did not produce significant effects against contraction produced by other vasoactive agents. SB 217242 produced concentration-dependent antagonism of responses produced by ETB receptor activation as demonstrated by antagonism of sarafotoxin S6c-mediated contraction in the rabbit isolated pulmonary artery with a Kb value of 352 nM. In vitro cell monolayers of Caco-2 cells had high permeability to SB 217242. In vivo pharmacokinetics in the rat confirmed that SB 217242 was rapidly absorbed from the gastrointestinal tract with a bioavailability of 66%. The SB 217242 plasma half-life in rats after intraduodenal administration was 3.3 hr, with a systemic clearance of 27.3 ml/min/kg. Orally administered SB 217242 (0.3-30 mg/kg) produced dose-dependent inhibition of the pressor response to exogenous ET-1 in conscious rats; with a dose of 30 mg/kg p.o., inhibition was observed for at least 5.5 hr. The present study demonstrates that SB 217242 is a highly potent antagonist of both ETA and ETB receptors. In addition, SB 217242 has high in vitro permeability and high oral bioavailability. SB 217242 represents a new orally active pharmacological tool that should assist in the elucidation of the chronic role of endothelin in pathophysiology.

[Photodynamic therapy of small adenocarcinomas with methylene blue]

Photodynamic therapy (PDT) is a new method in the treatment of small/early malignancies. It is based on the interaction of a photosensitiser, light and cellular oxygen. A new therapeutic concept with locally applied 1% of methylene blue into the tumour and subsequent radiation (argon laser pumped dye laser, 665 nm, 100 mW/cm2, 100 J/cm2) was first tested in xeno-transplanted carcinomas and then clinically applied. The animal experiments showed a tumour volume reduction of 1:12, as compared to a control group, two weeks after the first PDT-application. After the second PDT-treatment 6 out of 10 tumours were destroyed. Four carcinomas showed inhibited growth after the treatment. The method was clinically applied in 3 patients with local tumour recurrence in the area of the anastomosis after oesophagus resection. 72 hours after PDT-treatment 4-5 mm tumour necrosis could be proven experimentally. PDT was repeated at the same site within 2 weeks. There were no experimental or clinical complications during or after PDT. The treated tumour areas showed no local tumour growth within 6 months after PDT-treatment.

16S-23S and 23S-5S intergenic spacer regions of Streptococcus thermophilus and Streptococcus salivarius, primary and secondary structure

The 16S-23S intergenic spacer region (spacer region 1) of Streptococcus salivarius, S. thermophilus, and Lactococcus lactis subsp. cremoris and the 23S-5S intergenic spacer region (spacer region 2) of S. salivarius and L. lactis subsp. cremoris were sequenced and compared with the spacer regions 1 and 2 of other streptococci. A high degree of intraspecific conservation was observed for S. thermophilus and L. lactis, and very similar sequences were found for S. salivarius and S. thermophilus. Whereas spacer region 1 is highly conserved in the genus Streptococcus sensu-stricto, only the tRNA gene and the rRNA processing stems are highly conserved in the three genera: Streptococcus sensu-stricto, Lactococcus, and Enterococcus. The presence of a unique tRNA(Ala) gene without the 3' terminal CCA sequence seems to be a general feature of the streptococci spacer region 1. A secondary structure model was built to show the interaction between the spacer regions 1 and 2 of S. thermophilus and S. salivarius. The rapid evolution of spacer region 1 in streptococci is in part due to insertions and deletions of small RNA stem/loop structures.

Human tolerance and physiological responses to exercise while breathing oxygen at 2.0 ATA

Multiple physiological functions were monitored in ten men who performed two 30-min periods of 150-W ergometer exercise during 120-min exposures to O2 at 2.0 ATA. There were no convulsions or electroencephalographic manifestations of increased excitability. Sequential measurements of peripheral visual fields, pulmonary mechanical function, mental performance, and cardiovascular function during the resting recovery after each of the two exercise periods were not detectably altered from pre-exercise control values. Pre- and post-exposure measurements of visual acuity, accommodation, pupil diameter, visual cortical activity, and retinal electrical activity also revealed no significant differences. While CNS symptoms were absent, average arterial PCO2 rose by about 5 mm Hg during both exercise periods. This finding was confirmed in six subjects who performed four 6-min periods of continuous exercise at 50, 100, 150, and 200 W while breathing O2 at 2.0 ATA. Average arterial PCO2 rose nearly linearly from 34.3 mm Hg at rest to 44.0 mm Hg at 200 W. Arterial PCO2-related increments in brain blood flow and PO2 may explain part or all of the known detrimental influence of exercise on CNS O2 tolerance.

Nonpeptide endothelin receptor antagonists: IV. Identification of receptors in rabbit colonic mucosa and smooth muscle and correlation with physiological effects

Endothelin (ET) has been previously demonstrated to be a potent intestinal secretory stimuli and to elicit intestinal smooth muscle contractions. In rat distal colon, the ETA receptor antagonist cyclo[D-Asp-L-Pro-D-Val-L-Leu-D-Trp] abolishes the changes in ion transport (as measured by short-circuit current) elicited by ET-1. In this study, effects of ET-1, sarafotoxin 6c and "big" ET in the absence and presence of the endothelin receptor antagonists cyclo [D-Asp-L-Pro-D-Val-L-Leu-D-Trp] and (+/-)-3-[2-(carboxymethoxy)-4-methoxyphenyl]-1-[3,4- (methylenedioxy)phenyl]-5-(prop-1-yloxy)indan-2-carboxylic acid on ion transport in rabbit distal colon were assessed through measurement of short-circuit current changes in segments of muscle-stripped mucosa in Ussing chambers. In addition, changes in smooth muscle contraction in response to acetylcholine, ET-1, ET-3 and sarafotoxin 6c in the absence and presence of (+/-)-3-[2-(carboxymethoxy)-4-methoxyphenyl]-1-[3,4- (methylenedioxy)phenyl]-5-(prop-1-yloxy)indan-2-carboxylic acid and of cyclo [D-Asp-L-Pro-D-Val-L-Leu-D-Trp] were measured in mucosa-free preparations oriented along their longitudinal axes. Receptor binding studies with mucosal or smooth muscle homogenates were conducted with [125I]ET-1, with [125I]ET-3 and with [125I]Tyr13Suc-[Glu9,Ala11,15]-endothelin-1(8-21 ) to identify the subtypes of ET receptors present in these preparations. From studies with rabbit colonic mucosa, both binding studies and measurement of short-circuit current confirm that the ETB receptor subtype is the predominant subtype and is responsible for the changes observed in ion transport.(ABSTRACT TRUNCATED AT 250 WORDS)

Cortisol, corticotropin, and beta-endorphin responses to corticotropin-releasing hormone in patients with atopic eczema

Alterations in the hypothalamic-pituitary-adrenal (HPA) system are well documented in affective disorders. In depression these include increased secretion of cortisol, an insufficient suppressibility of cortisol by dexamethasone, a blunted corticotropin (ACTH) response to corticotropin-releasing hormone (CRH) and a dysfunction of the glucocorticoid receptor. Patients with atopic eczema, a common chronic skin disease, show seasonal variations in disease activity, symptoms of minor depression and immunological disturbances similar to those seen in patients with depression. To explore the integrity of the HPA system integrity in individuals with atopic eczema we studied the 24-h cortisol secretion and the cortisol, ACTH and beta-endorphin responses to CRH in such individuals and in healthy controls matched for sex and age. The 24-h secretion of cortisol did not differ between the patients with atopic eczema and the controls. The net response to CRH administered as a 100 micrograms i.v. bolus was significantly attenuated for both cortisol (24,235 +/- 12,443 vs. 47,019 +/- 34,515 nmol.min/dl; p < .03) and for ACTH (546 +/- 205 vs. 727 +/- 310 pmol.min/l; p < .05) in the patient group, whereas the beta-endorphin response did not differ between the groups (1072 +/- 448 vs. 1603 +/- 421 nmol.min/l). The blunted response of cortisol and ACTH cannot be explained by hypercortisolism as it is the case in major depression. Rather, it may be related to a prolonged underexposure to hypothalamic CRH or to an increased sensitivity of glucocorticoid feedback inhibition.

Determinants of hospital stay after modified radical mastectomy

The most expeditious way of reducing surgical costs is through reducing hospital stay. Multivariate analysis was used to identify potentially alterable factors affecting postoperative hospital stay for 73 consecutive patients undergoing modified radical mastectomy by 6 surgeons during a 12-month period. Stepwise logistic regression was used to identify independently significant preoperative variables associated with hospital stays equal to or greater than the median of 5 days. Intraoperative techniques and postoperative management were then evaluated using Cox proportional hazards model, with length of stay as the dependent variable after consideration for the significant independent preoperative factors. Age, history of heart disease, hypertension, diabetes, obesity, and American Society of Anesthesiologists (ASA) risk were significantly associated with prolonged stay (more than 4 days) in univariate analysis. Only age (P < 0.001) and cardiac history (P = 0.013) were significant independent predictors of hospital stay in multivariate analysis. After consideration for age and cardiac history, the only significant intraoperative or postoperative factor associated with hospital stay was the use of dressings incorporating Steri-Strips. This study suggests that the attribution of the reduction in hospital stay to discharge with drains in place is due to numerous factors, only one of which is the willingness to send patients home with the drains.

Cortisol and beta-endorphin responses to sleep deprivation in major depression--the hyperarousal theories of sleep deprivation

To test theories that response to sleep deprivation in depression is the result of either stress reactions or down-regulation of hyperarousal, the early morning cortisol and beta-endorphin levels of depressed sleep deprivation responders and nonresponders before and after sleep deprivation were compared (areas under the curve of 8 blood samples between 7:30 and 10 a.m.). The beta-endorphin response was significantly different in responders and nonresponders, whereas all other comparisons remained nonsignificant. The results do not support theories that sleep deprivation acts as a stressor, but are not contradictory to the hyperarousal hypothesis of sleep deprivation.

Biotransformation of 17 beta-hydroxy-11 beta-(4-dimethylaminophenyl)17 alpha-1-propynyl-estra-4,9-dien-3-one (RU486) in rat hepatoma variants

Metabolism of the synthetic steroid 17 beta-hydroxy-11 beta-(4-dimethylaminophenyl)17 alpha-1-propynyl-estra-4,9-dien-3-one (RU486) occurs in the dedifferentiated S-H56-125 variant of Reuber hepatoma. Considering that rat liver cytochrome P450 (P450) monooxygenases are engaged in different oxidative steps of the metabolism of RU486, the influence of several prototype P450 inducers was investigated. The data obtained by treating H56 and S-H56-125 hepatoma cells with different P450 inducers (dexamethasone (DEX), benzanthracene, phenobarbital) or with a specific P450 inhibitor, troleandomycin, led us to conclude that CYP3A is involved in the hydroxylation of RU486. This form is induced by DEX independently of the availability of the canonical glucocorticoid receptor.

Antiproliferative action of the steroid RU486 in cultured human lymphoma cells

The antiproliferative properties of the synthetic steroid RU486 on the human lymphoma cell line Daudi are described. In suspension cultures, RU486 (10 microM) caused a time dose and cell density dependent reduction of cell proliferation. This effect was reversed within 48 h of withdrawal of RU486 from the growth medium. High concentrations of foetal calf serum can mask the inhibitory effect. In semi-solid cultures RU486 also impaired cell proliferation. Thus RU486 was able to suppress in this tumor cell line the expression of some properties frequently associated with the transformed status of the cells.

Hypothermia induced by hyperbaric oxygen is not blocked by serotonin antagonists

Exposure to HBO causes hypothermia, bradycardia, head weaving, resting tremor, piloerection, and straub tail in rats. These physiological and behavioral responses can also be evoked by selective activation of serotonin1A (5-HT1A) receptors. The purpose of the current study was to determine if hypothermia caused by HBO is due to increased activation of 5-HT1A receptors. The levels of brain biogenic amines were measured in brain regions of Sprague-Dawley (SD) rats exposed to HBO. Exposure to HBO caused an increase in the levels of 5-hydroxyindoleacetic acid (5-HIAA) in the striatum (92%, p < 0.05) and occipital-temporal cortex (116%, p < 0.05), but not in other brain regions. Exposure to HBO did not change the levels of tryptophan, serotonin (5-HT), other biogenic amines, or their metabolites. It is hypothesized that the Fawn Hood (FH) rat, which is reported to be resistant to hypothermia induced by 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), has an abnormality of 5-HT1A receptor activity. Although the FH rat was more resistant to hypothermia induced by HBO than the SD rat, we were not able to confirm that this rat was resistant to hypothermia induced by 8-OH-DPAT. The 5-HT receptor antagonists, 1-(1H-Indol-4-yloxy)-3-[(1-methylethyl)amino]-2-propanol (Pindolol), 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl] piperazine hydrobromide (NAN-190), and methysergide, did not block hypothermia induced by HBO in SD rats. A series of control experiments were used to confirm that the antagonists blocked hypothermia induced by serotonin agonists.(ABSTRACT TRUNCATED AT 250 WORDS)

Invertebrate cytokines. III: Invertebrate interleukin-1-like molecules stimulate phagocytosis by tunicate and echinoderm cells

Phagocytosis is the predominant defense mechanism of invertebrates. Here we show that phagocytosis by echinoderm bladder amoebocytes and tunicate granular amoebocytes can be enhanced by invertebrate interleukin-1-like molecules. As little as 5 ng/ml of invertebrate interleukin-1 produced a significant stimulation of echinoderm and tunicate amoebocyte phagocytosis. Stimulation of phagocytosis by echinoderm interleukin-1-like molecules was inhibited by antisera to vertebrate interleukin-1. Invertebrate interleukin-1 also acted as an opsonin when preincubated with erythrocytes or yeast. In addition, the cellular mechanisms of invertebrate phagocytosis were studied using pharmacologic agents to inhibit echinoderm amoebocyte phagocytosis. The energy requirements and involvement of cellular cytoskeletal elements in phagocytosis by bladder amoebocytes were similar to those of mammalian macrophages. These results demonstrate a role for interleukin-1 in invertebrate host defense mechanisms.

Purification and immunological characterization of a major low-molecular-weight lipoprotein from Borrelia burgdorferi

Borrelia burgdorferi resembles gram-negative bacteria in having both cellular and outer membranes. We previously showed that a lipopolysaccharide (LPS)-like material could be extracted from B. burgdorferi with phenol-chloroform-petroleum ether (PCP). The PCP extract of B. burgdorferi exhibited biological activity in several in vitro assays (e.g., mitogenicity, pyrogenicity, and cytokine release). These activities suggested the presence of endotoxin. The PCP extract of B. burgdorferi, however, also contained a small amount of protein. Preliminary studies showed that monoclonal antibody prepared against this protein inhibited the mitogenic activity of the PCP extract toward murine spleen cells. The current study was therefore undertaken to characterize this protein and to establish methods for its separation from the LPS. The PCP-extracted protein consisted of a single, low-molecular-weight lipoprotein (apparent M(r), 10,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) (SDS-PAGE). By protein analysis, it accounted for 2% of the dry weight of defatted cells, thus making it a major constituent of the spirochete. It was purified from the LPS by initial extraction into 10% Triton X-100 followed by immunoaffinity chromatography in the presence of detergent. On removal of the LPS, the purified lipoprotein formed aggregates stable to SDS-PAGE which were detectable on Western blots (immunoblots) probed with either the monoclonal antibody or polyclonal antiserum. From a plot of the aggregate molecular weight versus aggregate size, a monomer molecular weight of 7,500 was obtained. Indirect immunofluorescence with the monoclonal antibody showed that the lipoprotein was exposed at the surface of the spirochete in only a small percentage of cells. The lipoprotein was present in several strains of B. burgdorferi but absent in other Borrelia spp., treponemes, and gram-negative human pathogens, indicating species specificity.

Mechanism for the recruitment of macrophages to cancer site. In vivo concentration gradient of monocyte chemotactic activity

BACKGROUND

Tumor stroma is characterized by the development of new blood vessels, an inflammatory cell infiltration, and a fibrotic reaction. The inflammatory component of tumor stroma plays an important role in the modulation of tumor expansion. In this respect, macrophages constitute a major part of the inflammatory cell infiltration and can exert cytotoxic activity against tumor cells. The accumulation of macrophages in the vicinity of the tumor suggests their recruitment from circulating blood monocytes through the local release of chemotactic factors for monocytes.

METHODS

To detect the existence of a concentration gradient of monocyte chemotactic activity (MCA) between the tumor vicinity and blood vessels, malignant pleural effusions defined by the local presence of cancer cells were evaluated for quantification of MCA.

RESULTS

Unlike nonmalignant pleural effusions, malignant pleural effusions were characterized by the presence of increased levels of MCA, and in lung adenocarcinoma (a cancer with high inflammatory cell infiltration), pleural levels of MCA were significantly greater than in small cell lung carcinoma (a cancer with low inflammatory cell reaction). An MCA concentration gradient between pleural fluid and plasma was present in malignant effusions because pleural MCA levels in all cancer types were significantly greater than MCA levels in the plasma of the same patients.

CONCLUSIONS

Thus, an increased local level of MCA is a feature of cancers with high inflammatory cell infiltration, and the presence of an in vivo concentration gradient of MCA suggests the direct role of this biologic activity in recruiting blood monocytes to the cancer site.

Mechanism for the recruitment of macrophages to cancer site. In vivo concentration gradient of monocyte chemotactic activity

BACKGROUND

Tumor stroma is characterized by the development of new blood vessels, an inflammatory cell infiltration, and a fibrotic reaction. The inflammatory component of tumor stroma plays an important role in the modulation of tumor expansion. In this respect, macrophages constitute a major part of the inflammatory cell infiltration and can exert cytotoxic activity against tumor cells. The accumulation of macrophages in the vicinity of the tumor suggests their recruitment from circulating blood monocytes through the local release of chemotactic factors for monocytes.

METHODS

To detect the existence of a concentration gradient of monocyte chemotactic activity (MCA) between the tumor vicinity and blood vessels, malignant pleural effusions defined by the local presence of cancer cells were evaluated for quantification of MCA.

RESULTS

Unlike nonmalignant pleural effusions, malignant pleural effusions were characterized by the presence of increased levels of MCA, and in lung adenocarcinoma (a cancer with high inflammatory cell infiltration), pleural levels of MCA were significantly greater than in small cell lung carcinoma (a cancer with low inflammatory cell reaction). An MCA concentration gradient between pleural fluid and plasma was present in malignant effusions because pleural MCA levels in all cancer types were significantly greater than MCA levels in the plasma of the same patients.

CONCLUSIONS

Thus, an increased local level of MCA is a feature of cancers with high inflammatory cell infiltration, and the presence of an in vivo concentration gradient of MCA suggests the direct role of this biologic activity in recruiting blood monocytes to the cancer site.

Invertebrate cytokines II: release of interleukin-1-like molecules from tunicate hemocytes stimulated with zymosan

Conditioned media and cell extracts from tunicate hemocytes that had been cultured with a variety of antigenic stimulants were tested for interleukin-1 (IL-1)-like activity. Media conditioned by hemocytes stimulated with zymosan significantly increased the proliferative and phagocytic activities of tunicate hemocytes. SDS-PAGE indicated that these biological activities were associated with the adaptive release of tunicate IL1-like (tunicate IL-1) molecules by stimulated hemocytes. The data suggest that tunicate IL1 molecules are expressed in response to selected antigenic stimuli. Such responses may form the basis for nonclonal, inducible immune reactions among phylogenetically primitive animals.

Role of the physiochemical properties of mucus in the protection of the respiratory epithelium

The respiratory mucus is a very complex biological material, which possesses both flow and deformation rheological properties, characterized by non-linear and time-dependent viscoelasticity and physical properties of adhesiveness and wettability. Viscosity and elasticity are directly involved in the transport capacity of mucus, whereas wettability and adhesiveness contribute to the optimal interface properties between the mucus and the epithelial surface. Optimal conditions for the protective and lubricant properties of respiratory mucus are represented by high wettability, and adhesiveness high enough not to induce flow of mucus in the respiratory bronchioles under gravity but low enough to mobilize mucus by airflow during coughing. An intermediate viscoelasticity is also required for an optimal mucociliary transport. Different biochemical constituents such as glycoproteins, proteins, proteoglycans and lipids are involved in the gel properties of respiratory mucus. During bronchial infection and particularly in cystic fibrosis, the loss of water and the increase in macromolecules result in a marked increase in viscosity and adhesiveness responsible for the mucus transport impairment. The various lipids present in mucus contribute differently to the physicochemical properties. Surface-active phospholipids, such as phosphatidylcholine and phosphatidylglycerol improve the wettability of mucus, whereas neutral lipids and glycosphyngolipids contribute to the hyperviscosity of mucus during infection. Phospholipids and associated mucins are also implicated in the interaction between bacteria and epithelial cells. Therefore, the respiratory mucus needs appropriate physicochemical properties for the protection, hydration and lubrication of the underlying airway epithelium.

Role of the physiochemical properties of mucus in the protection of the respiratory epithelium

The respiratory mucus is a very complex biological material, which possesses both flow and deformation rheological properties, characterized by non-linear and time-dependent viscoelasticity and physical properties of adhesiveness and wettability. Viscosity and elasticity are directly involved in the transport capacity of mucus, whereas wettability and adhesiveness contribute to the optimal interface properties between the mucus and the epithelial surface. Optimal conditions for the protective and lubricant properties of respiratory mucus are represented by high wettability, and adhesiveness high enough not to induce flow of mucus in the respiratory bronchioles under gravity but low enough to mobilize mucus by airflow during coughing. An intermediate viscoelasticity is also required for an optimal mucociliary transport. Different biochemical constituents such as glycoproteins, proteins, proteoglycans and lipids are involved in the gel properties of respiratory mucus. During bronchial infection and particularly in cystic fibrosis, the loss of water and the increase in macromolecules result in a marked increase in viscosity and adhesiveness responsible for the mucus transport impairment. The various lipids present in mucus contribute differently to the physicochemical properties. Surface-active phospholipids, such as phosphatidylcholine and phosphatidylglycerol improve the wettability of mucus, whereas neutral lipids and glycosphyngolipids contribute to the hyperviscosity of mucus during infection. Phospholipids and associated mucins are also implicated in the interaction between bacteria and epithelial cells. Therefore, the respiratory mucus needs appropriate physicochemical properties for the protection, hydration and lubrication of the underlying airway epithelium.

How the potency of the steroid RU486 is related to P450 activities induced by dexamethasone and phenobarbital in rat hepatoma cells

In a previous work on rat liver microsomes, we demonstrated that cytochrome P450 isozymes (P450) are engaged in the metabolism of RU486. In order to study the underlying mechanism at the molecular level, our investigations were shifted to a simplified system of cultured hepatoma cells which present a dissociation in the expression of distinct P450 coding genes. Our results show that Fao cells represent a convenient model to study both: (i) the degradation of RU486. Forms IIB1,2 and IIC7, which are present in Fao cells, may contribute to the demethylation of the molecule. Form IIIA, which has not been detected in Fao cells, is probably responsible for its oxidation in the liver; (ii) the effect of RU486 on the expression of P450 enzymes. Unlike other steroids (dexamethasone and pregnenolone 16 alpha-carbonitrile), RU486 does not induce P450 activity but inhibits the inducing activity of other agents such as dexamethasone and also phenobarbital. These findings may be important for the therapeutic use of RU486 since its inhibitory effect on P450 activity may be at the origin of drug interactions by modifying the endogenous hormonal status.

Inhibition of growth by the antihormone RU486 in different hepatoma cell lines

The synthetic steroid RU486 (17 beta-hydroxy-11 beta-(4-dimethylaminophenyl)-17 alpha-(1-propynyl)-estra-4,9-dien-3-one), which has been shown to display antiprogestin and antiglucocorticoid properties in different systems, exerts antiglucocorticoid effects and inhibits the cell growth in a concentration-dependent manner on Reuber rat hepatoma cell variants. This effect can be observed on glucocorticoid-sensitive cells, containing glucocorticoid receptors, and on glucocorticoid-resistant cells displaying a very low level of dexamethasone binding. Metabolization of RU486 occurs in different glucocorticoid-resistant hepatoma variants; these cells are less sensitive to the growth inhibitory effect of the antihormone than the steroid-sensitive cells which do not metabolize RU486. Thus, metabolization of RU486 must also be taken into account for the efficacy of this antagonist on cell growth.

Invertebrate cytokines: tunicate cell proliferation stimulated by an interleukin 1-like molecule

Tunicate pharyngeal cells include lymphocyte-like cells and granular amoebocytes. They are involved in the specific allogeneic and phagocytic reactions of tunicates. Little is known about their regulation or control. A tunicate interleukin 1 (IL-1)-like fraction is shown to stimulate the proliferation of these cells in vitro. This fraction, designated tunicate IL-1 beta, was isolated from tunicate hemolymph by gel filtration and chromatofocusing chromatography. Mitogenic responses to tunicate IL-1 beta were dose dependent and could be eliminated rapidly by removing tunicate IL-1 beta from culture medium. A second tunicate hemolymph fraction had no effect on tunicate cell proliferation even though it exhibited IL-1-like activity in a mouse thymocyte proliferation assay. Phytohemagglutin did not act synergistically with either fraction. These data are discussed in terms of the function and evolution of IL-1-like molecules in invertebrates.

Synthesis and biological activity of new HMG-CoA reductase inhibitors. 3. Lactones of 6-phenoxy-3,5-dihydroxyhexanoic acids

A group of 43 optically active sodium carboxylates (11a-qq and the corresponding lactones 4 were prepared from respective phenols 8 according to Schemes I-III. Phenols 8 were synthesized from commercially available compounds according to Schemes IV-IX. A number of these HMG-CoA reductase inhibitors 11 exceeded mevinolin's activity in vitro (Tables II and III). Selected lactones 4 effectively inhibited hepatic "de novo" cholesterol synthesis in rats in vivo (Table IV). After po administration to rabbits, 4ff(11ff), 4hh, and notably 11jj reduced plasma cholesterol levels more potently than mevinolin (Table V). Whereas 4ff(11ff) displayed the slight superiority expected according to in vitro data, 4hh and 11jj were considerably more potent than expected. Each of these compounds had only moderate activity after po administration to dogs (Table VI). Compound di-11ii, a hybrid of the structural elements of probucol and HMG-CoA reductase inhibitors, after po administration to rats decreased serum lipoproteins and increased HDL/LDL ratio better than probucol (Table VII). HMG-CoA reductase inhibitor 11ll and phenolic building blocks 8, notably 8jj and 8kk, inhibited LDL oxidation in vitro (Table VIII). Chemical structure-activity relationships (Table IX) and the pharmacological profile of phenoxy-type inhibitors 11 diverged from those of known HMG-CoA reductase inhibitors.

Activation of Epstein-Barr virus promoters by a growth-factor and a glucocorticoid

Transforming growth factor-beta (TGF-beta) and a glucocorticosteroid, Dexamethasone (DXM), both cause transcriptional induction of Epstein-Barr virus (EBV) early antigens (EA) in Daudi lymphoma cells. The viral induction occurs through the viral promoter DR overlapping an origin of replication which is active during the lytic cycle. Each hormone requires specific regions on the DR promoter. Since these regions also mediate the action of two viral transcription factors, EB1 and R, it may be emphasized that EB1 and/or R are involved in the EA induction process by TGF-beta and by DXM.

Mediators, initiating the inflammatory response, released in organ culture by full-thickness human skin explants exposed to the irritant, sulfur mustard

Mediators released from injured human skin that initiate the inflammatory response have not been adequately identified. Organ culture of full-thickness skin explants enables us to do so, because injury to the skin can be made in vitro, eliminating the rapid leakage of serum and infiltration of leukocytes that occur in vivo. In our studies, the military vesicant sulfur mustard (SM) (10 microliters of a 0.01 to 1.0% dilution) was topically applied to injure the epidermis of the explant. Then, the explants were cultured in small Petri dishes, usually for 18 h at 36 degrees C, and the organ-culture fluids were assayed for various inflammatory mediators. We found that the culture fluids from SM-exposed and control explants contained similar amounts of angiotensin-converting enzyme, trypsin-like and chymotrypsin-like proteases, acid phosphatase, beta-glucuronidase, beta-galactosidase, lysozyme, deoxyribonuclease, ribonuclease, interleukin 1, and lactic dehydrogenase. However, the culture fluids from SM-exposed explants contained increased amounts of histamine and plasminogen-activating activity, and often prostaglandin E2, when compared to culture fluids from control explants. After 3 to 4 d in culture, full-thickness human skin explants, when exposed to 0.2% SM (but not when exposed to 1.0% SM), sometimes showed separation of the epidermis and increased collagenase activity (i.e., hydroxyproline release). Thus, histamine (from local mast cells), and prostaglandin E2 and plasminogen-activating activity (probably from both mast cells and epidermal cells) are apparently involved in early mediation of the inflammatory response.

Primitive cytokines: harbingers of vertebrate defense

The evolution of the immune system has awarded cytokines a key role as coordinators of the immune response. The exquisite action of cytokines in fine tuning and controlling the response raises the question of whether or not these molecules have been highly conserved through evolution. Gregory Beck and Gail Habicht have isolated and characterized two major cytokines, interleukin 1 and tumor necrosis factor, from invertebrates. In this article, they speculate on the possible function of these molecules and on the existence of other cytokines in invertebrates.

Purification and biochemical characterization of an invertebrate interleukin 1

Interleukin 1 (IL-1) is a major immunoregulatory protein released by macrophages with many host defense related properties. That IL-1 has been found in the invertebrates attests to its importance in homeostasis. The first step in comparing the vertebrate protein to its invertebrate correlate is to purify the protein to study. We have purified to homogeneity IL-1 isolated from the coelomic fluid of the starfish Asterias forbesi. The IL-1 had isoelectric points of 7.4, 5.4 and 4.8. The pI 4.8 species had a molecular weight of 22,000 and the pI 7.4 and 5.4 species both had Mr of 17,000. Higher Mr forms were also found. These molecules were biologically active in the human melanoma A375 cytotoxicity assay for IL-1, and were also able to stimulate murine dermal fibroblast proliferation, protein synthesis, and PGE2 production. The pI 4.8 and 5.4 forms were purified to homogeneity and the amino acid composition was determined. The pI 4.8 and 5.4 species were purified more than 200-fold to specific activities of 3 x 10(6) and 1 x 10(6) units mg-1, respectively. The pI 7.4 form was isolated and partial N-terminal sequence analysis was performed. The similarities of molecular weight, isoelectric points and biological properties between vertebrate and invertebrate IL-1 show that it is an important, evolutionarily stable host defense molecule.

Disturbed glucocorticoid receptor autoregulation and corticotropin response to dexamethasone in depressives pretreated with metyrapone

We studied glucocorticoid receptor autoregulation and corticotropin response to dexamethasone in depressed patients and controls, attempting to control for the confounding effect of endogenous glucocorticoids. After depletion of endogenous cortisol, depressed patients showed an attenuated suppressibility of corticotropin by dexamethasone in the face of unchanged dexamethasone plasma levels. Beta-endorphin levels were strongly correlated with adrenocorticotropic hormone (ACTH) concentrations. Although metyrapone administration resulted in a marked rise of glucocorticoid receptor sites per cell in controls, this effect was not present in depressives. These data support the hypothesis of a decreased glucocorticoid receptor plasticity and a partial steroid resistance in depression.

Evidence for a functional glucocorticoid responsive element in the Epstein-Barr virus genome

Glucocorticoids induce the expression of Epstein-Barr virus early antigens in latently infected Daudi cells. By sequence analysis, we found that fragment C of the BamHI digested Epstein-Barr virus B95-8 genome contains a region with a large degree of homology to the glucocorticoid responsive element of known glucocorticoid-regulated genes. By transfection experiments in Daudi and HeLa cells, different lengths of this region, cloned in front of the bacterial chloramphenicol acetyl transferase linked to the Herpes Simplex virus thymidine kinase promoter (pBLCAT.2), were assayed for their responsiveness to dexamethasone; our results led us to the conclusion that the hormonal effect observed was mediated by a minimal sequence of 15 base pairs presenting 85% homology with the consensus glucocorticoid responsive element sequence.

The processed pseudogene of mouse thymidine kinase is active after transfection

Aside of the gene coding for cytoplasmic thymidine kinase, the genome of mouse cells carries two pseudogenes. Both are inactive in situ. One of the pseudogenes is a processed pseudogene in which a two base pair deletion caused a shift of the reading frame and a shortening of the gene product from the 233 amino acids of thymidine kinase to 177 amino acids in the pseudogene product. We report here that introduction of this pseudogene into LTK- cells gave rise to cells with a thymidine kinase positive phenotype. The transformed cells carried multiple copies of the pseudogene the upstream region of which exhibited low but measurable promoter activity. Replacement of the upstream region of the pseudogene by a promoter of Simian virus 40 or of the mammary tumor virus resulted in high transfection efficiencies and in cell lines exhibiting high thymidine kinase activities.

The steroid antagonist RU38486 is metabolized by the liver microsomal P450 mono-oxygenases

Microsomal preparations from adult male rat liver actively oxidized RU38486 into the 11 beta-monodemethylated, 11 beta-didemethylated and 17 alpha-hydroxylated derivatives, metabolites which are known to be formed in vivo. These oxidative reactions were inhibited at different degrees by P450 chemical inhibitors. Pretreatment of the animals by P450 mono-oxygenase prototype inducers led to drastic changes in RU38486 metabolization. Methylcholanthrene treatment carried out a significant decrease while phenobarbital markedly increased the metabolic activity of the liver microsomes. Moreover, antibodies to methylcholantrene-inducible P450 forms did not affect the metabolic activity while a complete blockade-of RU38486 oxidation was observed in the presence of antibodies to phenobarbital- inducible forms. The present results demonstrate that liver P450 mono-oxygenases are engaged in different oxidative steps of RU38486 metabolism and that phenobarbital-inducible but not methylcholanthrene-inducible P450 forms are active in RU38486 degradation.

Isolation, preliminary chemical characterization, and biological activity of Borrelia burgdorferi peptidoglycan

Peptidoglycan (PG), an essential cell wall polymer of most bacteria, has been isolated from many species of spirochetes. Our interest in the host response to Borrelia burgdorferi led us to isolate and characterize its PG. Extracted cells were solubilized with warm 1% SDS followed by digestion with proteases. Amino acid analysis of the isolated PG demonstrated the presence of alanine, glycine, glutamic acid, and ornithine as occurs in other spirochetes and bacteria. Intense erythematous reactions were observed after id injection of 10 micrograms of PG into normal human skin. PG was not mitogenic for human peripheral blood mononuclear cells. Murine splenocytes of certain strains responded to the PG, but only at concentrations of 25 micrograms/ml or more. PG stimulated macrophages to produce interleukin 1. Sixteen micrograms of PG injected iv into rabbits produced biphasic fevers. These observations on the in vitro and in vivo activities associated with the cellular components of the B. burgdorferi spirochete give further insight to how a small number of invading organisms can cause a multisystemic disease such as Lyme disease.

Vascular stenting in normal and atherosclerotic rabbits. Studies of the intravascular endoprosthesis of titanium-nickel-alloy

Percutaneous transluminal balloon angioplasty would be more effective if the rate of recurrent stenosis were reduced. To evaluate the prevention of restenosis after percutaneous transluminal angioplasty, intravascular endoprosthetic stents of titanium-nickel-alloy were implanted transluminally in seven normal and 21 atherosclerotic rabbits. In normal rabbits, a 3.5-mm diameter stent was implanted in the aorta and a 2.5-mm diameter stent in the right iliac artery, which were followed with serial angiograms from 6 weeks (n = 7) to 8 months (n = 4). There was a mean stenosis of 13.1% in the 2.5-mm and 13.6% in the 3.5-mm stent. There was no significant narrowing compared with the adjacent control segments of artery; histopathology showed a thin, fibrous neointima with smooth muscle cells. Each atherosclerotic rabbit was balloon dilated at two separate stenotic sites; each site was 2.0 cm in length. The aortic site (with 28.8 +/- 13.8% mean stenosis [+/- SD]) was dilated with a 3.5-mm balloon, and the iliac site (with 36.5 +/- 14.2% stenosis) was dilated with a 2.5-mm balloon. In each site, an intravascular stent of corresponding diameter and 7-mm length was implanted in one half of the dilated segment, assigned randomly, and the other half served as the angioplasty control. Angiographically observed restenosis rates and the corresponding histopathology were similar in the atherosclerotic segments that had angioplasty alone versus the atherosclerotic segments that had angioplasty plus stenting. The mean neointimal thickness in the aortas and iliac arteries, respectively, measured 247 +/- 181 microns (+/- SD) and 218 +/- 77 microns after 6 weeks (n = 8) versus 321 +/- 168 and 308 +/- 189 microns after 20 weeks (n = 5, p = NS). At 20 weeks follow-up, there was 29.1 +/- 29.8% (median, 16.4%) stenosis in the aortic stent versus 38.9 +/- 24.1% (median, 34.0%) stenosis in the percutaneous transluminal angioplasty control segment of aorta (n = 5, p = NS) and 81.4 +/- 25.5% stenosis in the iliac artery stent versus 89.3 +/- 15.3% stenosis in the PTA control segment of the right iliac artery (n = 5, p = NS). Comparing stenotic arterial segments treated with angioplasty alone with angioplasty plus intravascular stenting in the atherosclerotic rabbits showed that there was no significant difference in either the histopathologic changes or the restenosis rates.

Interaction of C1q with its receptor on cultured cell lines induces an anti-proliferative response

The receptor for human C1q (C1qR) is expressed on a wide variety of somatic cells, including cultured cell lines of different lineages such as Raji, Daudi, Wil2WT, U937, and Molt4. In this report, we present evidence which shows that culturing of C1qR-expressing cell lines with C1q inhibits their growth. When each of the different cell lines were cultured for 5 days with or without various concentrations (5-50 micrograms/ml) of micro-filtered (0.22 micron) C1q, cell proliferation was inhibited in a dose-dependent manner with maximal inhibition (90%) occurring at a concentration of 50 micrograms/ml at Day 4 of culture. This anti-proliferative effect of C1q was inhibited when 30 micrograms/ml of F(ab')2 anti-C1q was included in the culture with C1q while the antibody alone did not have any effect. The specificity of this interaction was further substantiated by the finding that neither macromolecular C1, or subcomponents C1r and C1s, nor human or murine IgG nor IgM had any inhibitory activity when cultured with these cell lines. That this C1q-induced inhibition of cell growth is mediated by C1qR was deduced from experiments in which (i) culturing of cells in the presence of two IgM monoclonal antibodies II1/D1 and II1/B5, directed against the C1q-binding site of C1qR resulted in the inhibition of cell growth while nonimmune murine IgM did not, and (ii) the collagenous portion of C1q (c-C1q) which contains the intact, C1qR-binding domain was also capable of inhibiting cell proliferation in a manner similar to intact C1q. The effect of C1q was not cytotoxic but cytostatic since the number of dead cells in the C1q-treated cultures was not significantly different than that in the untreated cells (5% vs 4%), a figure which represents the normal wear and tear of tissue culture conditions. On the basis of these findings we propose that the C1qR alone or in conjunction with other cellular factors may function as a molecule which supports cell growth. Upon ligand binding, however, the ligand-receptor interaction may suppress postreceptor events which are necessary for cell proliferation.

Synthesis and biological activity of new HMG-CoA reductase inhibitors. 1. Lactones of pyridine- and pyrimidine-substituted 3,5-dihydroxy-6-heptenoic (-heptanoic) acids

Lactones of pyridine- and pyrimidine-substituted 3,5-dihydroxy-6-heptenoic (-heptanoic) acids 2-4 have been synthesized. Extensive exploration of structure-activity relationships led to several compounds exceeding the inhibitory activity of mevinolin (1b) on HMG-CoA reductase, both in vitro and in vivo. First clinical trials with 2i (HR 780) are in preparation.

Synthesis and biological activity of new HMG-CoA reductase inhibitors. 2. Derivatives of 7-(1H-pyrrol-3-yl)-substituted-3,5-dihydroxyhept-6(E)-enoic (-heptanoic) acids

A series of 7-(1H-pyrrol-3-yl)-substituted-3,5-dihydroxyhept-6(E)- enoates (-heptanoates) 1 and 2 have been prepared and tested for inhibiti 3-hydroxy-3-methylglutaryl-coenzyme A reductase. The most potent compounds exceeded mevinolin's activity in vitro and in vivo.