Hypoxia stimulates the release by bovine pulmonary artery endothelial cells of an inhibitor of pulmonary artery smooth muscle cell growth

The proliferation of smooth muscle cells (SMC) seen in hypoxic pulmonary hypertension is a poorly understood phenomenon but may involve endothelial cell (EC)-SMC interaction. Using bovine pulmonary artery cells, we examined the effect of O2 tension and the role of EC or media conditioned by EC (ECCM) on SMC proliferation. We found no difference in SMC proliferation under 3%, 10%, and 20% O2. EC, co-cultured with SMC in 3% O2, inhibited SMC proliferation consistently by about 40% (versus SMC exposed to hypoxia but not to EC). In normoxia, the degree of inhibition was dependent on EC:SMC ratio. In separate experiments, media from EC exposed to 3% or 20% O2 had a mitogenic activity of 24% and 42%, respectively (compared to 100% mitogenic activity with 5% FCS), on serum-deprived SMC. On the other hand, when SMC were stimulated to grow with FCS, an inhibitory activity (IA) from ECCM on SMC proliferation was observed and was significantly greater in hypoxic versus normoxic ECCM (40% versus 21%, respectively). Amicon concentration showed that the IA was contained in the less than 10 kD fraction of ECCM. Preliminary characterization of this IA indicates that it is unlike any of the known inhibitors of SMC growth, such as lactic acid, prostaglandin derivatives, or heparan sulfate. We conclude that hypoxia causes pulmonary artery EC to release a unique inhibitor of SMC growth.

Smooth muscle cell conditioned medium elevates angiotensin-converting enzyme of bovine pulmonary artery endothelial cells

Conditioned medium obtained from bovine pulmonary artery smooth muscle cells (SMC) in culture was found to elevate angiotensin-I-converting enzyme (ACE) of bovine pulmonary artery endothelial cells (EC) by 2- to 3-fold upon incubation for 24 to 48 h. The elevation in ACE was time dependent and inhibited by 10(-6) M cycloheximide, making it likely that the elevation was related to new protein synthesis by EC. Conditioned medium from EC failed to produce the same effect. The stimulatory effect of SMC conditioned medium on EC ACE was uninfluenced by exposures to anoxia as compared with room air, either during conditioning of medium or while assaying the effect of conditioned medium on EC ACE. Inhibitors of prostaglandin metabolism and calcium transport failed to influence the stimulatory effect of SMC conditioned medium on EC ACE. The stimulatory effect on EC ACE by conditioned medium was additive to that produced by Ca2+ ionophore A23187 and 3-isobutyl-1-methylxanthine and, similar to baseline ACE, was inhibited by 3 x 10(-8) M ouabain. Thus, SMC produce a factor that regulates the level of EC ACE.

[A carotid resection in cervical tumors without a vascular reconstruction]

From 1979 to 1988, 15 cases, consisting of 12 carotid body paragangliomas, 1 vagal body paraganglioma, 1 aneurysm of the internal carotid artery, and 1 recurrent metastatic carcinoma of the neck, were given a simple carotid resection without a vascular reconstruction, since the lesions were fixed to the carotid artery. The collateral cerebral cross-flow was promoted preoperatively with the use of compressing exercises of the carotid artery and controlled by computerized rheoencephalography. There was no operative mortality, though a transient postoperative cerebral complication did occur in one female patient, from which she recovered in one month. Of this series of 15 patients, one died from a malignant lesion and 14 survived for 3 months to 9 years without cerebrovascular complications.

Reduction of calcium channel antagonist binding sites by oxygen free radicals in rat heart

In view of the importance of Ca2+-channels in controlling the entry of Ca2+ into the myocardium, this study was undertaken to examine the effects of oxygen free radicals on the binding of Ca2+-channel antagonists in rat heart by employing [3H]-nitrendipine as a ligand. Isolated heart membranes were incubated with xanthine + xanthine oxidase (a superoxide anion radicals generating system), hydrogen peroxide (an activated species of oxygen), or hydrogen peroxide + Fe2+ (a hydroxyl radicals generating system). The assay of the [3H]-nitrendipine binding activity revealed that the maximal number of binding sites (Bmax) were reduced in a time-dependent manner by superoxide radicals without any changes in the binding constant (Kd); a significant reduction of Bmax was seen after incubating membranes with xanthine + xanthine oxidase for a 10-min-period. Superoxide dismutase showed a protective effect on the superoxide radicals induced reduction in Bmax. Both hydrogen peroxide and hydroxyl radicals also depressed the Bmax for [3H]-nitrendipine binding without any significant change in Kd; catalase and mannitol showed protective effects on hydrogen peroxide or hydroxyl radicals induced depression in Bmax, respectively. These results indicate that oxygen free radicals may reduce the number of Ca2+-channels in the cell membrane and this change may contribute towards decreasing the voltage-dependent Ca2+ influx in the cardiac cell.

Altered sympathetic system and adrenoceptors during the development of cardiac hypertrophy

Increasing experimental evidence suggests that the development of cardiac hypertrophy may involve the sympathetic system and associated receptor mechanisms. However, very little work has been done so far to understand changes in the sympathetic system and cardiac adrenoceptors soon after an increased work load is imposed on the heart. Accordingly rat hearts subjected to aortic banding-induced pressure overload were assessed 3, 7, and 14 days postoperatively. Sham-operated rats without aortic banding were used as a control group. Rats with aortic constriction had increases in heart rate, left ventricular systolic pressure, and total mechanical energy during the entire study period. The cardiac RNA level was increased without a significant increase in left ventricular mass on days 3 and 7 in aortic-banded animals; these results were associated with a decrease in the cardiac norepinephrine (NE) store and an increase in the plasma level of NE and dopamine beta-hydroxylase (DBH) activity. By day 14 a significant increase in left ventricular mass and the NE store were found; both plasma NE and DBH remained elevated. Catecholamines in other tissues such as the spleen and kidney were depleted in the banded group, whereas the dopamine level, particularly in the brain, was significantly higher during the entire study. Furthermore, the density of alpha-adrenoceptors was higher on day 3 of aortic banding, and a reciprocal correlation was evident between cardiac alpha- and beta-adrenoceptors on day 14; the density of beta-adrenoceptors was increased, whereas that of alpha-adrenoceptors was decreased in the banded group.(ABSTRACT TRUNCATED AT 250 WORDS)

Activation of heart sarcoplasmic reticulum Ca++-stimulated adenosine triphosphatase by insulin

Although insulin is known to elicit a positive inotropic effect in cardiac muscle preparations, very little is known concerning the mechanism of this action. In view of the crucial role played by the sarcoplasmic reticular (SR) calcium transport in cardiac contractile events, the effects of insulin on the pig heart SR were investigated. Insulin activated the SR Ca++-stimulated adenosine triphosphatase (ATPase) in a concentration-dependent manner (0.1 mU to 1 U/ml); maximal activation (125%) was seen at 0.1 to 1 U/ml of insulin. Kinetic studies revealed that the insulin-induced activation was due to an increase in the apparent Vmax of Ca++-stimulated ATPase without any alteration in the Km. Insulin was found to bind with SR membranes in a specific manner and this binding was rapid, saturable and displacable. The dose-related increase in the activation of Ca++-stimulated ATPase was related linearly (r = 0.98) to binding of insulin with SR membranes; 50% activation of Ca++-stimulated ATPase was found to occur at 13.5 fmol of insulin binding per mg of SR protein. When insulin was allowed to dissociate by a 100-fold dilution of the insulin-receptor complex, the activity of SR Ca++-stimulated ATPase also declined gradually. Furthermore, proteolytic digestion on the membrane with trypsin (3 micrograms/mg of protein) decreased both insulin binding as well as the increase in Ca++-stimulated ATPase activity by about 50%.(ABSTRACT TRUNCATED AT 250 WORDS)

Endothelial cell inhibition of hypoxia-induced stimulation of serotonin uptake by vascular smooth muscle cells

Exposure of bovine pulmonary artery smooth muscle cells (SMC) to anoxia for 24 h resulted in an approximate twofold stimulation of serotonin (5-HT) uptake compared with SMC exposed to 20% O2. The stimulation of 5-HT uptake by exposure to anoxia was eliminated when bovine pulmonary artery endothelial cells (EC) were cocultured with SMC. Incubation with EC-conditioned medium produced similar inhibitory effects on 5-HT uptake of SMC exposed to anoxia, a result not seen with SMC-conditioned medium. The inhibitory effect of EC-conditioned medium on the anoxia-stimulated 5-HT uptake was concentration dependent and absent at a dilution of 1:16. The production of the inhibitor was time-dependent. The EC-derived inhibitory factor was heat-stable at 100 degrees C for as long as 10 min and was stable in a pH range from 5.0 to 10.0. Significant losses of inhibitory activity of EC-conditioned medium were observed after treatment with trypsin, pronase E, and proteinase K. The molecular weight on the inhibitory factor from EC-conditioned medium was estimated to be approximately 66,000 by size-exclusion chromatography. The data show that stimulated uptake of 5-HT by SMC under anoxic conditions is under regulation by a protein (or polypeptide) produced by EC.

Measurement of boar sperm motility by the trans-membrane migration method

The conventional microscopic methods for evaluating sperm motility of domestic animals are mostly inadequate due to their subjectivity and lack of precision. Recently, a trans-membrane migration method, originally developed for the examination of human sperm motility, has substantially overcome these problems. This study investigated the applicability of the method to boar sperm motility measurement. The apparatus used was simple and consisted only of syringe plungers, poriferous membranes, and modified multi-well culture plates. It measured the proportion of sperm in the semen that moved across the membrane after incubation at 37 degrees C for 3 hr. The sperm motility as measured by this method correlated well with that measured by direct microscopic examinations. The measurement was more reliable using an 8-microns instead of a 5-microns pore-size membrane. The method was found to work equally well for the sperm motility measurement of the semen with a sperm concentration between 1.5 x 10(8)/ml and 6.0 x 10(8)/ml. The results indicate that this method is a simple, objective, quantitative, and reproducible design for the measurement of boar sperm motility.

Interleukin-1 beta stimulates somatostatin biosynthesis in primary cultures of fetal rat brain

Interleukin-1 (IL-1), a secretory product of activated macrophages and many other cell types, is an important mediator of the acute phase reaction to infection and to endotoxin administration. Previous reports that GH and TSH secretion are decreased following injection of endotoxin or IL-1 led us to test the hypothesis that IL-1 acts by releasing increased amounts of somatostatin (SS), a hypothalamic factor inhibitory of both GH and TSH release. Primary cultures of dispersed fetal rat diencephalic cells were found to contain increasing amounts of immunoreactive SS in both cells and media after addition of recombinant human IL-1 beta. This increase was detectable at 24 hours and continued for up to 6 days, the longest time interval tested. Increased content of SS peptide was accompanied by marked increases in SS mRNA. These changes were dose-related, the lowest effective dose being 10(-10) M. In contrast to the long term response, exposure of the cells to IL-1 beta for one hour had only minimal stimulating effects on somatostatin release. These data indicate that IL-1 beta is neurotrophic for the somatostatinergic neuron, an action that may be responsible at least in part, for the neuroendocrine response to infection.

Effects of exogenous vasoconstrictors on coronary vascular resistance and prostacyclin production of the quiescent heart: the inhibitory effect of aspirin

The in situ heart is exposed to blood-borne vasoconstrictor agents (e.g., vasopressin) which, if unopposed, may cause radically increased coronary vascular resistance (CVR). Release of endogenous vasodilator, such as prostacyclin (PGI2), is a possible mitigating mechanism. We investigated the ability of the heart to maintain CVR within a narrow range when exposed to exogenous vasoconstrictors. The isolated rat heart was perfused at constant flow rate (5-6 ml/min) with oxygenated Krebs-Ringer bicarbonate solution (37 degrees C, pH 7.4), and was rendered quiescent by a local injection of lidocaine to the atrio-ventricular node. Changes of perfusion pressure, indicating changes of CVR, were monitored and the cardiac effluent was collected for analysis of 6-keto PGF1 alpha and thromboxane B2 (stable metabolites of PGI2 and thromboxane A2, respectively) by radioimmunoassay. Hearts were infused with four different vasoconstrictors (i.e., serotonin, vasopressin, angiotensin II and the thromboxane A2/PGH2 mimetic, U46619). There was a linear relationship between the dose-dependent increase in CVR and PGI2 production in serotonin, U46619 and vasopressin-infused quiescent heart. Vasoconstriction induced by angiotensin II was not dose-dependent and was unrelated to PGI2 production. Thus, PGI2 is produced in response to coronary vessel constriction, presumably to mitigate the constriction. No detectable thromboxane B2 was released by any of these vasoconstrictors. Partial inhibition (approximately 50%) of PGI2 production by aspirin (5.6 microM) treatment resulted in a paradoxically decreased vasoconstriction except at the lowest level of serotonin and vasopressin. Aspirin (1 mM) greatly reduced PGI2 production (approximately 90%) but the fall in CVR persisted.(ABSTRACT TRUNCATED AT 250 WORDS)

Serotonin uptake and configurational change of bovine pulmonary artery smooth muscle cells in culture

Although it is well known that endothelial cells transport serotonin (5-HT) from extracellular to intracellular locations, it has been generally assumed that smooth muscle cells do not accumulate 5-HT but, rather, respond to 5-HT through a receptor activity unrelated to uptake of this amine or via stimulation of endothelial-derived relaxing factor. In the present study smooth muscle cells (PASMC), isolated and cultured from bovine pulmonary artery, were evaluated for 5-HT uptake under a variety of conditions. 5-HT uptake was linear up to 15 min and the rate was seven- to eightfold higher than that by bovine pulmonary artery endothelial cells. There was intracellular metabolism of 5-HT to 5-hydroxyindoleacetic acid (5-HIAA). The uptake was inhibited by exposure to 4 degrees C, absence of Na+ from the medium, and agents such as imipramine, verapamil, ketanserin, and methiothepin. Like that of endothelial cells, 5-HT uptake by PASMC was stimulated by exposure of cells to anoxia for 24 hr. Unlike endothelial cells that showed no morphological changes, PASMC at early passage showed dendritic formation after 30-60 min exposure to 5-HT at a concentration as low as 10(-8) M. Although this configurational change in response to 5-HT was lost with passage of cells, transport of 5-HT by these cells was retained. The configurational change was blocked by agents that inhibited 5-HT uptake, such as imipramine, verapamil, ketanserin, and methiothepin; it was unaffected by inhibitors of protein kinase C, phospholipase C, and calmodulin or absence of Ca2+ from the medium. We conclude that PASMC, as well as endothelial cells, accumulate 5-HT; there appears to be a close relationship between 5-HT uptake and configurational change of early passaged PASMC in culture. The factor(s) required for the configurational change are absent in endothelial cells and lost during passage of PASMC.

Structure of the gene encoding rat thyrotropin releasing hormone

The gene encoding the hypothalamic peptide thyrotropin releasing hormone (TRH) was isolated from two rat genomic bacteriophage libraries. Southern blot analysis indicates that the gene is present as a single copy in the rat genome. The transcriptional unit is 2.6 kilobases in size and contains three exons interrupted by two introns of approximately 750 and 450 base pairs. Exon 1 encodes the 5'-untranslated region of the mRNA, exon 2 encodes the signal sequence and the majority of the amino-terminal peptide, and exon 3 encodes the remainder of the amino-terminal peptide, five copies of the TRH sequence, the carboxyl-terminal peptide, and the 3'-untranslated region of the mRNA. The general structure of the TRH gene resembles that of three other polypeptide hormone genes, preproopiomelanocortin, preproenkephalin A, and preproenkephalin B. Further sequence analysis revealed that characteristic promoter elements are present in the 5'-flanking region of the TRH gene. In addition, sequence homologies with the glucocorticoid receptor binding site, the GC box hexanucleotide, and a portion of the flanking region of the thyroid stimulating hormone beta-subunit gene were also identified. These upstream sequences may be important for the regulation of TRH gene expression.

High prevalence of serum antibodies to reverse transcriptase in HIV-1-infected individuals

The HIV immunoblot profiles of 700 HIV-antibody-positive sera were examined to determine the frequency of antibody reactivity with p66/p51, the reverse transcriptase of HIV. We report a remarkably high seroprevalence of antibodies to p66/p51, detected in 79% of the sera. Only gp41 is recognized more frequently in these assays. The level of anti-p66/p51 seroreactivity varies only slightly among the clinical stages of HIV infection.

Verapamil inhibits serotonin uptake of endothelial cells in culture by a mechanism unrelated to Ca2+ channel blockade

Verapamil inhibited Na+-dependent uptake of serotonin (5-HT) by bovine pulmonary artery endothelial cells in culture both exposed to room air and stimulated by prior exposure to anoxia. The effect of verapamil occurred even in the absence of Ca2+ from the assay medium. Although absence of Ca2+ from the medium moderately reduced 5-HT uptake, stimulation of uptake was nevertheless observed for cells previously exposed to anoxia. Verapamil altered the Km, but not the Vmax, of 5-HT uptake. There was no change in 45Ca2+ uptake or release by cells previously exposed to anoxia as compared to those exposed to room air and verapamil did not influence 45Ca2+ fluxes by either set of cells. It is concluded that verapamil inhibits 5-HT uptake by endothelial cells through a mechanism other than Ca2+ channel blockade; the results are consistent with competitive inhibition of a 5-HT carrier. The stimulatory effect of anoxia on 5-HT uptake does not occur through a change in Ca2+ fluxes.

Glycolytic activity and enhancement of serotonin uptake by endothelial cells exposed to hypoxia/anoxia

Serotonin (5-HT) uptake by bovine pulmonary artery endothelial cells in culture was stimulated several fold by exposure of cells for 24 hours to 0-3% O2. The cells appeared normal morphologically, excluded trypan blue dye, showed normal levels of release of lactate dehydrogenase, and contained normal amounts of adenosine triphosphate (ATP). Incubation of cells with iodoacetate (3-5 microM), an inhibitor of glycolytic metabolism, prevented the stimulation of 5-HT uptake but did not impair cellular proliferation. A similar, but less pronounced, effect was produced by 1 mM deoxyglucose. On the other hand, the mitochondrial inhibitors antimycin A, sodium azide, potassium cyanide, and 2,4-dinitrophenol inhibited cellular replication similar to the effect of anoxia but did not alter the stimulation of 5-HT uptake. 5-HT uptake correlated strongly with lactate production by the cells exposed to anoxia (r = 0.98). We conclude that stimulation of 5-HT uptake by prolonged exposure of the endothelial cell to hypoxia/anoxia causes alteration of a membrane function (serotonin transport) of the endothelial cell. This alteration is associated with enhanced glycolytic activity of the cell during exposure to hypoxia. The mechanism for translation of enhanced glycolysis to later stimulation of 5-HT uptake remains to be determined. Endothelial cellular replication is dependent on aerobic metabolism.

The quiescent heart: excitability, compliance, and vascular resistance

A rat heart, perfused via the aorta and fitted with a balloon in the left ventricle, was rendered quiescent by a local injection of lidocaine into the region of the atrioventricular node. Once quiescence was established it was extended by injection of formaldehyde into the same site via a coaxial needle. The quiescent heart (QH) was responsive to electrical stimulation and exhibited the same isovolumic pressure development as seen during spontaneous beating. Over a range of ventricular volume, slightly greater left ventricular pressures were found in the QH as compared with the diastolic pressure at the same ventricular volumes in the beating heart (BH). Left ventricular diastolic pressures in the QH were less than those found in the KCl-arrested heart. The QH perfused at constant flow rate with a syringe pump exhibited a constant perfusion pressure. Infusion of vasopressin induced a dose-related increase in perfusion pressure, whereas adenosine or sodium nitroprusside reduced the perfusion pressure. The QH appears to be a useful preparation for the study of vascular resistance free of cyclical intramyocardial pressure and relatively uninfluenced by vasoactive metabolites arising from contracting muscle.

Reversibility of ultrastructural, contractile function and Ca2+ transport changes in guinea pig hearts after global ischemia

To understand the subcellular basis of contractile failure due to ischemia-reperfusion injury, effects of 20, 60, and 90 min of global ischemia followed by 30 min of reperfusion were examined in isolated guinea pig hearts. Cardiac ultrastructure and function as well as Ca2+ transport abilities of both mitochondrial and microsomal fractions were determined in control, ischemic, and reperfused hearts. Hearts were unable to generate any contractile force after 20 min of ischemia and showed a 75% recovery upon reperfusion. However, there were no significant changes in the subcellular Ca2+ transport in the 20-min ischemic or reperfused hearts. When hearts were made ischemic for 60 and 90 min, the recovery of contractile force on reperfusion was 50 and 7%, respectively. There was a progressive decrease in mitochondrial and microsomal Ca2+ binding and uptake activities after 60 and 90 min of ischemia; these changes were evident at various times of incubation period and at different concentrations of Ca2+. Mitochondrial Ca2+ transport changes were only partially reversible upon reperfusion after 60 and 90 min of ischemia, whereas the microsomal Ca2+ binding, uptake and Ca2+ ATPase activities deteriorated further upon reperfusion of the 90-min ischemic hearts. Ultrastructural changes increased with the duration of the ischemic insult and reperfusion injury was extensive in the 90-min ischemic hearts. These data show that the lack of recovery of contractile function upon reperfusion after a prolonged ischemic insult was accompanied by defects in sarcoplasmic reticulum Ca2+ transporting properties and structural damage.

Impairment of mitochondrial and sarcoplasmic reticular functions during the development of heart failure in cardiomyopathic (UM-X7.1) hamsters

The oxidative phosphorylation as well as calcium transporting properties of heart mitochondria and calcium transport activities of the fragments of the sarcoplasmic reticulum (microsomes) were studied during the life span of cardiomyopathic hamsters (UM-X7.1). Control healthy hamsters of the same age group were used for comparison. No changes in the oxidative phosphorylation ability of cardiomyopathic mitochondria were seen at early and moderate stages of heart failure; however, at severe stages, mitochondrial respiratory functions, but not the ADP:0 ratio, were impaired. Both creatine phosphate and ATP contents were decreased without any significant changes in the ATPase activities of myofibrils from the failing hearts. Heart mitochondria from cardiomyopathic animals at severe stages of failure exhibited less calcium binding and uptake activities in comparison with the control values whereas no changes in the mitochondrial calcium binding and uptake were seen in cardiomyopathic hamsters which showed no clinical signs of heart failure. Although mitochondrial calcium binding in cardiomyopathic hearts at early and moderate stages of failure was decreased, mitochondrial calcium uptake was not significantly different from the control. Microsomal calcium binding activity, unlike calcium uptake activity, was decreased in the hearts of cardiomyopathic hamsters without any signs of heart failure. Both calcium binding and calcium uptake activities of microsomes from animals with early, moderate and severe heart failure were less in comparison with the control values but were not associated with any changes in the Ca2+-stimulated ATPase activity. These results suggest that changes in the process of mitochondrial energy production and mitochondrial Ca2+-transport may be secondary to other factors whereas alterations in the sarcoplasmic reticular Ca2+-transport may lead to the development of heart failure in the cardiomyopathic hamsters.

Serotonin uptake by bovine pulmonary artery endothelial cells in culture. II. Stimulation by hypoxia

Exposure of bovine pulmonary artery endothelial cells to 3% O2 resulted in approximately twofold stimulation of serotonin (5-HT) uptake after 24-48 h when compared with cells exposed to 20% O2. The enhanced uptake was reversed after 48 h when cells were again placed in 20% O2. The stimulation was not observed after 0.5 or 2 h of exposure to hypoxia. The stimulation was present when iproniazid blocked conversion of 5-HT to 5-hydroxyindole-3-acetic acid, indicating that enhanced uptake did not occur through augmentation of monoamine oxidase activity. Stimulation of uptake by hypoxia occurred at low concentrations of 5-HT (up to 10(-6) M) but not at high 5-HT concentrations (greater than 10(-5) M) and was blocked by imipramine or absence of sodium from the medium, indicating that high-affinity transport and not diffusion of 5-HT was stimulated. Furthermore, exposure of cells to hypoxia did not produce morphological evidence of injury or change in protein content or trypan blue exclusion. The cell number of 3% O2-exposed cells was slightly reduced when compared with controls after 48 h. There was no change in cellular ATP or increase in lactate dehydrogenase in medium of cells exposed to 3% O2. Thus exposure of endothelial cells in culture to hypoxia stimulates the membrane activity of 5-HT accumulation with no evidence of injury to the cell.

Serotonin uptake by bovine pulmonary artery endothelial cells in culture. I. Characterization

Serotonin (5-HT) uptake by bovine pulmonary artery endothelial cells in culture was measured at 5-HT concentrations of 1.5 X 10(-8) to 10(-3) M. The uptake increased linearly at concentrations of 10(-5) to 10(-3) M 5-HT, and the slope for uptake was 1.276 X 10(6) pmol 5-HT X 10(6) cells-1 X 30 min-1 X M concentration-1. The slope for uptake at 5-HT concentrations less than 10(-7) M was 7.10 X 10(6) pmol X 10(6) cells-1 X 30 min-1 X M concentration-1. With subtraction of the slope for linear uptake obtained at high concentrations of 5-HT from total uptake of 5-HT, a curve showing saturable uptake at concentrations greater than 10(-6) to 10(-5) M was obtained. Lineweaver-Burk analysis of the data yielded a saturated value of high-affinity transport of 6.25 pmol X 10(6) cells-1 X 30 min-1 and a Km of 10(-6) M. At 5-HT concentrations of 1.5 X 10(-8) to 5 X 10(-7) M, uptake was inhibited 75-80% by exposure to 4 degrees C or by absence of sodium in the medium; absence of sodium did not affect uptake at 5-HT concentrations greater than 10(-5) M, and 4 degrees C was less effective in inhibiting uptake at high 5-HT concentrations. Imipramine markedly inhibited uptake at low, but not at high, 5-HT concentrations. Ouabain only partially inhibited 5-HT uptake, but inhibition was more pronounced at low 5-HT concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Establishment of a large collection of extracted teeth for research

A collection of over 14,000 teeth extracted at the Prince Philip Dental Hospital since 1982 has been organized and catalogued on a computerized database management system. The computer catalogue provides, for each tooth in the collection, information on the age and sex of the patient, and the date of extraction and condition of the tooth. The catalogue can be searched according to any combination of the descriptive variables in the database record. Researchers, including visiting scientists, can borrow teeth from the central "tooth library" on a temporary or permanent basis. Further information on particular teeth (e.g. patient's medical and dental histories, dental radiographs) can be obtained from patients' charts. Establishment of this collection has greatly facilitated the work of researchers in clinical dentistry, dental anatomy, and dental anthropology.

Effects of hypoxia and hyperoxia on proteoglycan production by bovine pulmonary artery endothelial cells

Bovine pulmonary artery endothelial cells in culture were used to assess the influence of oxygen tension on proteoglycan synthesis. Cells exposed to 3% O2 (hypoxia) for 72 h and then labeled with [35S]sulfate for 5 h accumulated significantly less [35S]proteoglycan in medium than cells exposed to 20% O2 (control). This decrease was due primarily to a reduction in heparan sulfate. Cells exposed to 80% O2 (hyperoxia) for 72 h secreted slightly more [35S]proteoglycan into medium than controls. Greater accumulation of chondroitin sulfate was responsible for the increase. The amount of cell-associated proteoglycan did not change significantly in cells cultured in 3% or 80% O2 as compared with control cells cultured in 20% O2. Proteoglycans produced by hypoxia- or hyperoxia-treated cells were found to be similar in size to proteoglycans produced by cells cultured at 20% O2. Glycosaminoglycan sulfation, as measured by ion-exchange chromatography, did not appear to change with varying oxygen tensions. Our results demonstrate that production of proteoglycans secreted by endothelial cells in culture is sensitive to oxygen tension.

Serum zinc, copper, and ceruloplasmin levels in male alcoholics

Twenty male alcoholics aged 29 to 69 years (mean 45.80 + SD 10.97) were compared with controls for serum zinc, copper, and ceruloplasmin levels. The serum zinc level of the alcoholic patients was significantly lower than that of the control group (t = 3.3005, p less than 0.005). The serum copper and ceruloplasmin levels of the alcoholics tended to be higher than those of the controls, but the difference was not statistically significant. A significantly positive correlation between serum zinc and albumin levels (r = 5.41, p less than 0.01) was also found. The nutritional state of the alcoholics may not be an adequate explanation for their low serum zinc level. It is suggested that further research on alcohol as a toxic agent might focus on trace element-containing enzymatic defects in brain peptides and hormones to promote fuller understanding of the psychopathology associated with alcohol abuse.

Collagen-factor VIII/von Willebrand factor protein interaction

Factor VIII/von Willebrand factor (FVIII/vWF) protein interaction with collagen was studied by incubating plasma or purified FVIII/vWF with purified type I fibrillar collagen. Collagen adsorbed FVIII/vWF activities in a similar time and concentration-dependent manner from normal plasma, plasmas from classical and variant type von Willebrand's disease (vWD), and from purified FVIII/vWF. Incubation with denatured collagen or fibrin, produced in the presence or absence of fibronectin, showed no adsorption of FVIII/vWF. Examination of the multimeric structure of the remaining unadsorbed FVIII/vWF protein by agarose gel electrophoresis and autoradiography showed that the largest multimers had been adsorbed to the collagen. Studies of the adsorbed FVIII/vWF protein when eluted from collagen showed that it complemented the alterations in multimeric structure observed in the supernatants following collagen exposure. The multimeric structure of normal plasma following collagen adsorption resembled that of unadsorbed type IIb plasma; however, the collagen-adsorbed normal plasma did not produce enhanced ristocetin-induced platelet aggregation ( RIPA ). This phenomenon, therefore, must not be due solely to absence of large multimers from type IIb FVIII/vWF protein. The adsorbed multimers of FVIII/vWF protein may act as a subendothelial collagen-platelet bridge to promote primary hemostasis.

31P nuclear magnetic resonance spectroscopic evidence for ternary complex formation of fetal dentin phosphoprotein with calcium and inorganic orthophosphate ions

The single phosphoprotein of fetal calf dentin, having a molecular weight of approximately 94,000 and a phosphorus content of 8% (w/w), was examined by 31P NMR spectroscopy. The single resonance at 3.7 ppm at pH 10 and its chemical shift during acid titration established the phosphomonoester nature of the organic phosphorus moiety. During titration of the phosphoprotein with CaCl2 in the presence of inorganic orthophosphate ions, line broadening for the orthophosphate resonance was both phosphoprotein- and calcium-dependent, indicating ternary complex formation. The data indicate that the phosphoprotein of fetal calf dentin binds both calcium and inorganic orthophosphate ions and therefore has the requisite physical chemical properties necessary for it to facilitate the heterogeneous nucleation of a Ca-PO4 solid phase from solution during tissue mineralization.

Ultrastructural changes in bovine pulmonary artery endothelial cells exposed to 80% O2 in vitro

Bovine pulmonary artery endothelial cells in culture were exposed for up to 7 d to a gas mixture containing 80% O2, 5% CO2, and 15% N2 (hyperoxia) and were compared by phase contrast and electron microscopy to cells exposed to a gas mixture containing 20% O2, 5% CO2, and 75% N2. Cells exposed to hyperoxia became enlarged and showed vacuolization and increased lysosomes within 24 to 48 h. These changes were progressive over the 7 d period of exposure. Between 3 and 7 d of exposure to hyperoxia the cells showed reductions in polysomes and endoplasmic reticulum. Despite the other marked cytoplasmic changes, the appearance of mitochondria of oxygen-exposed cells remained unchanged from those of air-exposed cells throughout the 7 d period. Preconfluent and confluent cells responded qualitatively similarly to hyperoxia, but morphological evidence of injury occurred more rapidly for preconfluent cells. We conclude that the initial early structural injury of the endothelial cell exposed to hyperoxia occurs in lysosomes and that the mitochondrial structure is relatively resistant to injury.

Optimal conditions for long term storage of native collagens

Cryopreservation was used to maintain the biological activity of collagen, i.e., its fibril formation property, after isolation from tissues. Freezer temperatures commonly available in laboratories, -15 degrees C and -90 degrees C, and liquid nitrogen temperature, -196 degrees C, were compared for efficacy in preserving both type I collagen structure (amino acid and subunit composition, triple helix) and activity (fibril formation in vitro). Whether the collagen was stored dry or in acetic acid solution at -196 degrees C, the kinetics of fibril formation were completely stable for at least two and a half years, but decreased after several months storage at -15 degrees C or -90 degrees C. Types II and III collagens, also with intact nonhelical ends, are also completely stable in liquid nitrogen for at least two and a half years.

Immune restoration and/or augmentation of local graft versus host reaction by traditional Chinese medicinal herbs

The in vitro restorative effect of aqueous extracts from two traditional Chinese medicinal herbs were studied in 19 cancer patients and in 15 normal healthy donors. Using the local graft versus host (GVH) reaction as a test assay for T-cell function, the extract from astragalus membranaceus (10 microgram/ml) induced a restored reaction in nine of ten patients with an increase in local GVH reaction from 18.2 plus/minus 15.8 mm3 to 112.9 plus/minus 94.2 mm3 (P less than 0.01). The extract from ligustrum lucidum, likewise effected an immune restoration in nine of 13 cancer patients with an increase in local GVH reaction from 32.3 plus/minus 36.1 mm3 to 118 plus/minus 104.9 mm3 (P less than 0.01). This degree of immune restoration appears to be complete as it equals the local GVH reaction observed among untreated mononuclear cells from normal healthy donors (82.8 plus/minus 41.1 mm3, P greater than 0.1). These results suggest that both extracts of the traditional Chinese medicinal herbs contain potent immune stimulants which may provide the rational basis for their therapeutic use as biological response modifiers.

Phosphoproteins of bovine dentin: evidence for polydispersity during tooth maturation

The ethylenediaminetetraacetic acid extractable phosphoproteins of dentin from very young fetal calves consisted principally of a monodisperse species with an apparent molecular weight of at least 94 000 and a phosphorus content of 8.0% (w/w). In contrast, the soluble phosphoproteins extracted from mature adult animals under identical conditions ranged in molecular weight from 18000 to 94000 and contained less phosphorus. The data support the conclusion that the phosphoproteins of bovine dentin are degraded in vivo during mineralization and maturation of the tissue.

Type II collagen from lathyritic rat chondrosarcoma: preparation and in vitro fibril formation

Intact type II collagen monomer was isolated in 10-20% yield from lathyritic rat chondrosarcoma and purified to homogeneity. On warming in neutral solution, the collagen formed a mixture of D-periodic native fibrils and thin filaments with no apparent structure. There were characteristic lag and growth phases in the turbidity profile. cooling dispersed or dissolved the fibrils leaving thin filaments. The fibrils were very wide, up to 2.0 micrometers compared to the 10 to 40 nm fibrils present in situ. They had the appearance of stiff tactoids compared to the very long and flexible fibrils obtained from type I collagen under similar conditions. Type II collagen also required higher temperatures and concentrations than type I to form fibrils. The continued presence of thin filaments when type II fibril formation was complete suggests either that filaments are in slow equilibrium with fibrils or that they may not be intermediates but rather a separate product.

Ultrastructural changes of bovine pulmonary artery endothelial cells irradiated in vitro with a 137Cs source

Bovine pulmonary artery endothelial cells in culture were evaluated by phase-contrast and electron microscopy at various times after being irradiated with 137Cs in vitro. Cells irradiated prior to reaching confluency showed vacuolization aand increased numbers of lysosomes beginning at 48 hr after irradiation with 300-500 rad and at 24 hr after irradiation with 1500-5000 rad. After 7 days the morphological changes appeared to be reversible for cells receiving the lower doses, but were progressive for higher doses of radiation. The same qualitative changes, with a delayed onset, were observed for cells irradiated at confluency. An observed decrease in the endoplasmic reticulum and polysomes occurred only late in the course of radiation injury. There was no observable structural alteration of mitochondria even when there was evidence of otherwise marked cytoplasmic injury. We conclude that structural changes of the lysosomes constitute an early phase of injury by irradiation of the endothelial cell in culture, while decreases in endoplasmic reticulum and polysomes occur relatively late. The mitochondrial structure of the endothelial cell appears to be relatively resistant to radiation. All morphological changes occur subsequent to impaired transport of alpha-aminoisobutyric acid, which is observed within 6 hr as previously reported.

Purification, composition, and 31P NMR spectroscopic properties of a noncollagenous phosphoprotein isolated from chicken bone matrix

Fractionation of the EDTA-soluble, noncollagenous proteins of the organic matrix of chicken bone by Sephadex G-100 molecular sieving has revealed that the majority of the organic phosphorus is present in two fractions, from one of which a homogeneous phosphoprotein has been isolated. The purified phosphoprotein has an apparent molecular weight of 12,000 and contains both O-phosphoserine and O-phosphothreonine. 31P-NMR spectroscopy demonstrates that all of the organic phosphorus exists in the form of phosphomonoesters which have an average pK2 of 6.8. The phosphoprotein is highly acidic due to its high content of dicarboxylic acids in addition to the presence of organic phosphorus. The characteristic amino acid composition of the phosphoprotein establishes its noncollagenous nature and highlights the differences among bone, dentin, and enamel phosphoproteins. The absence of gamma-carboxyglutamic acid distinguishes it from osteocalcin, the noncollagenous gamma-carboxyglutamic acid-containing peptide of bone matrix.

Subcellular calcium transport during contractile failure and recovery in heart perfused with Na-free medium

Perfusion of isolated rat hearts with Na-free medium resulted in an immediate increase in contractile force followed by a decline and complete loss of contractile force within 25 s. The recovery of the contractile force upon reperfusion was only partial if the duration of Na-free perfusions was 10 min or longer. Ca binding and uptake activities of mitochondria obtained from hearts perfused with Na-free medium did not change significantly. However, Ca binding and uptake activities of microsomes were depressed after 5 min of perfusion. The critical concentration of Na in the perfusion medium for inducing these changes was found to be less than 35 mM. The microsomal Ca-ATPase activity was decreased after 10 min of Na-free perfusion. Only partial recovery of microsomal Ca uptake was observed upon reperfusion of hearts preperfused with Na-free medium for 20 min or longer whereas Ca-ATPase activity in these hearts did not recover at all. These results suggest that the defect in the microsomal Ca transport may be secondary to the development of contractile failure and may partially be associated with the inability of Na-depleted hearts to recover fully their contractile force.

Cooperativity in calcium ion binding to repetitive, carboxylate-serylphosphate polypeptides and the relationship of this property to dentin mineralization

Analogs of phosphophoryn, a calcium-binding phosphorylated protein found in mineralized dentin, were synthesized by solid phase peptide synthesis. The dentin phosphophoryn appears to contain some sequence blocks of (Asp-PhosphoSer)n. As this sequence is difficult to synthesize, polymers of (alpha-L-Glu-L-Ser) were prepared. The 30-peptide, (alpha-L-Glu-L-Ser)15, was phosphorylated by reaction with orthophosphoric acid in the presence of trichloroacetonitrile in anhydrous dimethylsulfoxide. Calcium ion binding studies were carried out with both the 30-peptide and phosphorylated 30-peptide. The conformation of the original 30-peptide, (Glu-Ser)15, was examined, in the presence and absence of calcium ion, by circular dichroism measurements. Purified bovine phosphophoryn, previously studied by the same techniques, was partially dephosphorylated by alkaline phosphatase, and its calcium ion binding properties were determined. Dephosphorylation to 31% of the initial phosphorus content reduced the number of high affinity sites to approximately 30% of the initial value. However, the stoichiometry of binding indicated that both phosphate and carboxylate groups participate in the high affinity binding and that the binding constant was decreased only slightly. Partial phosphorylation of the 30-mer raised the calcium binding constant, Ka, from 2.1 x 10(2) to 3.3 x 10(3) M-1 and increased the amount of binding from an electrostatic equivalent number of sites to a stoichiometric equivalent number. Concomitant with binding, there was a transition from random coil to beta-like structure. These data suggest that the repetitive (Asp-PhosphoSer)n regions in phosphophoryn and the (Glu-PhosphoSer)n sequence of the synthetic polymer have special conformations which favor the unidentate binding of calcium to the carboxyl groups and phosphate groups. and which enhance the binding affinities of the carboxyl groups in such sequences in a cooperative fashion.

Histiocytic lymphoma fifteen years following remission of acute lymphoblastic leukemia

A 19-yr-old female presented with diffuse histiocytic lymphoma after a 15-yr remission of acute lymphoblastic leukemia. All treatment had been discontinued 7 yr before the onset of the lymphoma. The possible relationships of these two neoplasms are discussed.

Subcellular Ca2+ transport in different areas of dog heart

Calcium transport and ATPase activities were determined in the heavy and mitochondrial fractions isolated from the left and right atria as well as ventricles of dogs. Ultrastructural distribution of these organelles in different areas of the myocardium was also examined. Calcium binding, calcium uptake, and calcium ATPase activities of the atrial microsomes were lower than those of the ventricles. On the other hand, mitochondrial calcium binding and uptake activities in the right atrium were higher than those in other areas. The mitochondrial total ATPase activities in the atria were also higher than those in the ventricles. Mitochondrial as well as microsomal yields from ventricles were significantly higher. Size and number of mitochondria in the ventricles were greater whereas no striking difference in the distribution of sarcoplasmic reticulum was apparent in different areas of the heart. Poorly developed calcium transport functions in the atrial microsomes may be one of the factors responsible for the generation of lower contractile force in this tissue in comparison with the ventricle.