Synthetic SP Research Articles

Gold nanoparticle assisted colorimetric biosensors for rapid polyethylene terephthalate (PET) sensing for sustainable environment to monitor microplastics

The extremely widespread and ubiquitous nature of plastics, estimated to boost its global production by 26 billion tons till 2050. The large chunks of plastic waste that decomposed down to micro- or nano plastics (MNPs) leads to various ill effects on biological entities. The conventional PET detection methods lack rapid detection of microplastics due to variances in microplastic features, long-drawn-out sample pre-processing procedures and complex instrumentation. Therefore, an instantaneous colorimetric evaluation of microplastic will ensures the simplicity of conducting assays on field. Several nanoparticle-based biosensors that detects proteins, nucleic acids, metabolites operate on either cluster or disperse state of nanoparticle. However, gold nanoparticle (AuNPs) emerges an ideal scaffold for sensory element in lateral flow biosensors due to their simple surface functionalization, unique optoelectronic properties and varied colour spectrum depending on morphologies and aggregation state. In this paper an effort has been made in the form of a hypothesis using in silico tools as a basis to detect polyethylene terephthalate (PET) – most abundant type of microplastic using gold nanoparticle based lateral flow biosensor. We retrieved sequences of PET-binding synthetic peptides and modelled their 3-D structure using I-Tasser server. The best protein model for each peptide sequences are docked with PET monomers – BHET, MHET and other PET polymeric ligands, to evaluate their binding affinities. The synthetic peptide SP 1 (WPAWKTHPILRM) docked with BHET and (MHET)4 exhibits 1.5-fold increases in binding affinity as compared to reference PET anchor peptide Dermaseptin SI (DSI). The GROMACS molecular dynamics simulation studies of synthetic peptide SP 1 - BHET & - (MHET)4 complexes for 50 ns further confirmed the stable binding. RMSF, RMSD, hydrogen bonds, Rg and SASA analysis provides useful structural insights of the SP 1 complexes as compared to reference DSI. Furthermore, SP 1 functionalized AuNP-based colorimetric device was described in detail for detection of PET.

A spiropyran-based colorimetric probe for quantitative analysis of cyanide ions in cassava leaves

A synthetic spiropyran derivative (2-(8-(hydroxymethyl)-3′,3′-dimethyl-6-nitrospiro [chromene-2,2′-indolin]-1′-yl)ethanol; SP) was spectroscopically evaluated as a highly selective probe and applied for colorimetric detection of cyanide ion (CN−) in cassava leaves. Upon addition of CN− into a pink solution of SP in THF/H2O (4.5:5.5 v/v, 0.5 mM HEPES at pH 9), a vivid yellow solution of the [MC-CN]− adduct was clearly observed by the naked eye. The spectral change in absorbance of the mixture between SP and CN− was monitored by UV–visible spectroscopy. The adduct formation through nucleophilic addition was confirmed by 1H NMR experiments. Additionally, the results from Job's plot suggested that SP and CN− formed the adduct at a 1:1 stoichiometric ratio with the binding constant of 8 × 104 M−1. The detection limit was determined to be 0.52 μM which is lower than the maximum permissible level of CN− in drinking water (1.9 μM) as approved by WHO. Moreover, the analysis of CN− in cassava leaves using our synthetic SP was demonstrated by both qualitative and quantitative approaches. The average CN− concentration in cassava leaves determined by the SP probe was 204.2 ppm which is comparable to the value obtained from the standard Chloramine-T/Pyridine-barbituric acid colorimetric method (203.6 ppm). The viable paper-test strips of SP were also developed for CN− colorimetric detection.

Imaging with pre-stack migration based on Sp scattering kernels

SUMMARYSp receiver functions have been widely used to detect the lithosphere–asthenosphere boundary (LAB) and other mantle discontinuities. However, traditional common conversion point (CCP) stacking can be biased by the assumption of horizontal layers and this method typically underestimates scattering amplitudes from velocity boundaries with significant dips. A new pre-stack migration method based on recently developed Sp scattering kernels offers an alternative that more accurately captures the timing and amplitude of scattering. When calculating kernels, Sp-S times are estimated with the fast-marching method, and scattering amplitude versus direction, geometrical spreading and phase shifts are accounted for. To minimize imaging artefacts with larger station spacing, Sp receiver functions are interpolated to more closely spaced pseudo-stations using either compressive sampling or spatial averaging algorithms. To test the kernel-based stacking method, synthetic Sp phases were predicted using SPECFEM2D for velocity models with a flat Moho and a negative mantle velocity gradient with a ramp structure. The kernel-based stacking method resolves horizontal interfaces equally well as CCP stacking and outperforms CCP stacking when imaging boundaries with dips of more than 8°, although dip resolution is still limited. Use of more vertically incident phases such as SKSp improves retrieval of dipping discontinuity segments. A second approach is to down-weight the portions of the kernels that have the greatest positive interference among neighbouring stations, thus enhancing scattering from dipping structures where positive interference is lower. With this downweighting, the kernel-based stacking method applied to Sp data is able to continuously resolve LAB discontinuities with dips up to 15° and to partially resolve continuous LAB discontinuities with dips of ∼20°. The intrinsic properties of teleseismic Sp phase kernels limit their ability to resolve LAB structures with dips of ∼20–35°, but still larger dips of ∼40–50° are resolvable with dense and appropriately placed stations. Analysis of Sp scattering kernels also explains the effectiveness of CCP stacking for quasi-horizontal interfaces.

Biomimetic N-Terminal Alkylation of Peptoid Analogues of Surfactant Protein C

Surfactant protein C (SP-C) is a hydrophobic lipopeptide that is critical for lung function, in part because it physically catalyzes the formation of surface-associated surfactant reservoirs. Many of SP-C's key biophysical properties derive from its highly stable and hydrophobic α-helix. However, SP-C's posttranslational modification with N-terminal palmitoyl chains also seems to be quite important. We created a new (to our knowledge) class of variants of a synthetic, biomimetic family of peptide mimics (peptoids) that allow us to study the functional effects of biomimetic N-terminal alkylation in vitro. Mimics were designed to emulate the amphipathic patterning, helicity, and hydrophobicity of SP-C, and to include no, one, or two vicinal amide-linked, N-terminal octadecyl chains (providing a reach equivalent to that of natural palmitoyl chains). Pulsating bubble surfactometry and Langmuir-Wilhelmy surface balance studies showed that alkylation improved biomimetic surface activities, yielding lower film compressibility and lower maximum dynamic surface tensions. Atomic force microscopy studies indicated that alkyl chains bind to and retain segregated interfacial surfactant phases at low surface tensions by inducing 3D structural transitions in the monolayer's fluid-like phase, forming surfactant-associated reservoirs. Peptoid-based SP-C mimics are easily produced and purified, and offer much higher chemical and secondary structure stability than polypeptide-based mimics. In surfactant replacements intended for medical use, synthetic SP mimics reduce the odds of pathogen contamination, which may facilitate the wider use of surfactant treatment of respiratory disorders and diseases.

Characterization of a New Thermophilic Spore Photoproduct Lyase from Geobacillus stearothermophilus (SplG) with Defined Lesion Containing DNA Substrates

The Geobacillus stearothermophilus splG gene encodes a thermophilic spore photoproduct lyase (SplG) that belongs to the family of radical S-adenosylmethionine (AdoMet) enzymes. The aerobically purified apo-SplG forms a homodimer, which contains one [4Fe-4S] cluster per monomer unit after reconstitution to the holoform. Formation of the [4Fe-4S] cluster was proven by quantification of the amount of iron and sulfur per homodimer and by UV and EPR spectroscopy. The UV spectrum features a characteristic absorbance at 420 nm typical for [4Fe-4S] clusters, and the EPR data were found to be identical to those of other proteins containing an [4Fe-4S]+ center. Probing of the activity of the holo-SplG with oligonucleotides containing one spore photoproduct lesion at a defined site proved that the enzyme is able to turn over substrate. In addition to repair, we observed cleavage of AdoMet to generate 5'-deoxyadenosine. In the presence of aza-AdoMet the SplG is completely inhibited, which provides direct support for the repair mechanism.

Localization of self‐potential sources in volcano‐electric effect with complex continuous wavelet transform and electrical tomography methods for an active volcano

This study concerns the fluid flow circulation associated with magmatic intrusion during volcanic eruptions from electrical tomography studies. The objective is to localize and characterize the sources responsible for electrical disturbances during a time evolution survey between 1993 and 1999 of an active volcano, the Piton de la Fournaise. We have applied a dipolar probability tomography and a multi‐scale analysis on synthetic and experimental SP data. We show the advantage of the complex continuous wavelet transform which allows to obtain directional information from the phase without a priori information on sources. In both cases, we point out a translation of potential sources through the upper depths during periods preceding a volcanic eruption around specific faults or structural features. The set of parameters obtained (vertical and horizontal localization, multipolar degree and inclination) could be taken into account as criteria to define volcanic precursors.

Differently cross-linked and uncross-linked carboxy-terminal telopeptides of type I collagen in human mineralised bone

In bone matrix, type I collagen is stabilised by covalent cross-links formed between adjacent collagen molecules; the majority of which is believed to be immature, divalent bonds. For studying these immature forms in detail, we have developed an immunoassay for a synthetic peptide SP 4 that is analogous with and detects a linear epitope within the C-telopeptide of α1-chain of type I collagen. The SP 4 assay, together with the ICTP assay, which is specific for the trivalently cross-linked C-telopeptide, was used for the isolation of the differently cross-linked C-telopeptide structures of the α1-chain of type I collagen present in mineralised human bone. Amino acid analysis, peptide sequencing and MALDI-TOF mass spectrometry were used to identify and characterise each of the isolated structures. The cross-link content of each isolated peptide was identified. In the trivalent ICTP peptide, only 40% was cross-linked with pyridinoline, the remainder of the cross-links being currently uncharacterised. The divalent peptides contained only previously characterised cross-linking structures. Most of the divalent cross-links were dihydroxylysinonorleucine (DHLNL), with minor amounts of hydroxylysinonorleucine (HLNL). The relative proportion of the HLNL cross-link was slightly higher in the divalent α1Cα2H peptide. A substantial amount of uncross-linked telopeptide structures was also found. Previous studies, where direct chemical cross-link analyses have been used to assess the maturity of cross-linking, have inferred that bone contains more divalently than trivalently cross-linked C-telopeptides. The immunochemical peptide approach used in this study may help to detect presently uncharacterised, trivalent cross-links, the presence of which is strongly suggested in this study. It also provides additional information regarding the extent and maturity of tissue type I collagen cross-linking in health and disease.

The Use of Matroclinous Maize Haploids for Recurrent Selection

Two cycles of recurrent selection were performed in maize with the use of matroclinous haploids. Two synthetic populations, SP and SA, were improved. Each cycle consisted of two stages: (1) isolation of haploids from the synthetic populations and (2) growth of the haploids, pollination with pollen from diploid plants, and selection. The selection was performed for ear size in haploid plants. The mean gain in productivity in the synthetic populations SP and SA the per cycle was 16.48 and 20.98%, respectively. It is suggested that the high value of this index is related to the fact that haploid plants reveal useful genes with additive and epistatic effects. Natural selection may have played a part, too. The combination of artificial and natural selection in haploids resulted in a considerable gain in productivity in the synthetic populations to be improved.

Evaluation of different types of synthetic adsorbents for carotene extraction from crude palm oil

AbstractPalm carotene was successfully concentrated from crude palm oil (CPO) by an adsorption process using synthetic adsorbents followed by solvent extraction. This process was a modified process for separation of palm carotene from CPO by adsorption chromatography with a synthetic polymer adsorbent. Carotene was concentrated to about 15,000 ppm, which is about 25 times the original concentration in CPO. Carotene recovery varied from 30 to 62% depending on the process conditions. Different types of adsorbents, combinations of adsorbents, and adsorbent/CPO ratios were evaluated to determine the effect on the percentage of carotene extracted. Commercial synthetic adsorbents HP 20 (styrene‐divinyl copolymer); synthetic aromatic porous resin SP 850, SP 825; and synthetic adsorbents Relite Exa 32 and Relite Exa 50 were capable of adsorbing substantial amounts of carotene from CPO. Combinations of adsorbents types HP 20 and SP 850 slightly increased the percentage of carotene extracted. An adsorbent/CPO ratio of 4 was most suitable for this process for optimal recovery and concentration of carotene.

Substance P inactivating enzymes in human cerebrospinal fluid

The K m and V max values were determined for enzymes in human lumbar cerebrospinal fluid (CSF) that inactivate synthetic substance P ( SP = RPKPQQFFGLM-NH 2 ) and produce metabolic products. For the human lumbar CSF samples analyzed in this study, K m = 2.24 ± 0.93 mM and V max = 0.113 ± 0.035 nmol/ml/min ( n = 10; mean ± SEM) for the rate of decrease of SP. HPLC analysis of the incubated synthetic peptide fragments demonstrated that the primary enzymatically produced fragment is SP(3–11), with minor amounts in decreasing order of SP(1–4), SP(1–7), and SP(1–9). Electrospray ionization mass spectrometry (ESI-MS) confirmed the appropriate molecular weights for the four peptides, SP(3–11), SP(1–4), SP(1–7), and SP(1–9). These data demonstrate that the primary enzyme in human lumbar CSF that acts on synthetic SP is a post-proline cleaving enzyme (PPCE).

Increased fecundity of the cladoceran Moinodaphnia macleayi on a diet supplemented with a green alga, and its use in uranium toxicity tests

The effects of two synthetic diets and four algal diets on the survival and fecundity of Moinodaphnia macleayi for use in life-cycle toxicity tests were determined. The synthetic foods were a suspension of blended cichlid fish pellets with powdered alfalfa, either prepared fresh or fermented in natural water for 3 days. The algae, isolated from the habitat of M. rnacleayi in the Alligator Rivers Region, were Selenastrum sp., Ankistrodesmus (falcatus?), Scenedesmus quadricauda and a Chlamydomonas sp. Each alga was tested alone or as a supplement to the fermented synthetic food. The diet that supported the greatest number of young and the highest survival rate over a 5-day period was a combination of the fermented synthetic food and Chlamydomonas sp. Analysis of the fatty acid composition of the lipid fraction of the four algal species showed that Chlamydomonas sp., Selenastrum sp. and Scenedesmus quadricauda had significant concentrations of the highly unsaturated fatty acids 18 : 2(n-6), 18 : 3(n-6) and 18: 3(n-3). In terms of size and dry weight, Chlamydomonas sp. was the smallest of the algal cells studied. The toxicity of uranium to M. macleayi survival, determined under standard conditions, was a lowest-observed-effect concentration (LOEC) of 200 �g L-1 after 48 h and 25 �g L-1 after 5 days.

The effects of substance P and calcitonin gene-related peptide on the efflux of endogenous glutamate and aspartate from the rat spinal dorsal horn in vitro

Bath applied SP (2 × 10 −7 to 5 × 10 −7 M) produced a significant increase in the concentration of glutamate in the spinal slice perfusate, whereas the efflux of aspartate increased only with a higher concentration of SP (5 × 10 −6 M). The enhancement of the basal efflux of glutamate persisted in the absence of external Ca 2+, but the effect was blocked by ( d-Arg 1, d-Pro 2, d-Trp 7,9, Leu 11)-SP, a SP analogue claimed to be an antagonist of synthetic SP. Calcitonin gene-related peptide (CGRP 10 −7 M) produced a significant increase in the concentrations of glutamate and aspartate in the perfusate. Neonatal capsaicin treatment prevented the SP-induced increase in the release of glutamate. In contrast, the effect of CGRP was not significantly modified by the capsaicin treatment. These results indicate that SP and CGRP are capable of modulating the basal efflux of endogenous aspartate and glutamate and this modulation may represent one of the mechanisms by which these peptides contribute to primary afferent synaptic transmission.

Substance P‐like immunoreactivity in human cerebrospinal fluid

In a study to elucidate molecular mechanisms in pain, substance P-like immunoreactivity (SP-LI) was measured in lumbar CSF from 75 patients with lower back pain. Two samples--one before and one after lidocaine treatment--were obtained from each patient, and total SP-LI was measured in unfractionated (no HPLC) samples. SP-LI data were separated into three categories: placebo responders, pharmacological responders, and pharmacological non-responders. A significant difference was observed between the total SP-LI measurement of first and second samples of pharmacological non-responders. Distribution of SP-LI immunoreactive molecular species in two CSF patient samples (no ODS) was analyzed with a combination of reversed phase (RP) HPLC and RIA. Immunoreactivity in collected HPLC fractions was measured at calibrated retention times of synthetic SP-sulfoxide (SP-O), SP, and SP. Qualitative and quantitative differences in those HPLC-RIA metabolic profiles were observed within and between those two patients' samples. These data indicate that the type and amount of SP metabolism and SP precursor-processing differs in CSF between these two representative patients and within the short amount of time elapsed between acquiring these two samples.

Substance P and gastrin releasing peptide in bovine mesenteric lymphatic vessels: Chemical characterization and action

Alcoholic extracts of bovine mesenteric lymphatic vessels were assayed for the presence of SP, GRP, VIP, PHI, GIP and NT using specific radioimmunoassays. SP and GRP immunoreactivities were detected at concentrations of 190±20 and 1,000±130 pg· g −1 , respectively. No significant levels of immunoreactivity were detected for any of the other peptides. SP and GRP immunoreactivities coeluted with their synthetic counterparts from both Sephadex G-50 and reversed phase HPLC columns. Synthetic SP (10 −9–10 −7 M) and the naturally occurring analogue of GRP, bombesin (10 −9–10 −7 M), increased spontaneous contraction rate in isolated vessel segments. This excitatory effect was not blocked by the α-adrenoceptor antagonist phentolamine ( 3×10 −6 M ).

Innervation of the large arteries and heart of the toad (Bufo marinus) by adrenergic and peptide-containing neurons

The innervation of the major arteries and heart of the toad (Bufo marinus) was examined by use of glyoxylic acid-induced catecholamine fluorescence and peptide immunohistochemistry. All arteries possessed a moderate to dense plexus of adrenergic axons, which also showed neuropeptide Y-like immunoreactivity (NPY-LI). Some adrenergic axons in the intracardiac vagal trunks showed NPY-LI, but the varicose adrenergic axons innervating the cardiac muscle of the atria and ventricle, and the coronary blood vessels did not display NPY-LI. About half of the nerve cell bodies in the anterior sympathetic chain ganglia with dopamine-beta-hydroxylase-LI (DBH-LI) also contained NPY-LI. The nerve cell bodies with DBH-LI alone were generally larger (median diameter 30 micron) than those with both DBH-LI and NPY-LI (median diameter 20 micron). Some cell bodies showing DBH-LI alone were surrounded by boutons with NPY-LI but not DBH-LI. Axons that displayed simultaneously both substance P-LI (SP-LI) and calcitonin gene-related peptide-LI (CGRP-LI) also formed a plexus around all arteries studied, being particularly dense around the mesenteric and pulmonary arteries. These axons are most likely sensory since SP-LI was reduced by capsaicin treatment, and nerve cell bodies with both SP-LI and CGRP-LI were found in dorsal root ganglia and the vagal ganglion. A dense plexus of axons showing somatostatin-LI was located around the pulmonary artery and its main intrapulmonary branches. A few nerves with vasoactive intestinal polypeptide-LI were found around the dorsal aorta and pulmonary artery. No perivascular nerves with enkephalin-LI were observed. Reversed-phase, high-pressure liquid chromatography of acid extracts of the large arteries showed that the major peaks of NPY-LI and SP-LI co-eluted with porcine NPY (1-36) and synthetic SP (1-11), respectively. Thus, the location and structure of these peptides in perivascular nerves has been highly conserved during vertebrate evolution.

Characterization of substance P-like immunoreactivity in submammalian species by high performance liquid chromatography

Substance P-like immunoreactivity (SP-LI) as measured by RIA was found to be present in a variety of submammalian species and invertebrates. We analyzed this SP-LI in extracts from submammalian species by high performance liquid chromatography. The following species were investigated for the presence of SP-LI (RIA) which was further characterized by subsequent HPLC (investigated areas in parentheses): Hagfish (brain plus spinal cord), rainbow trout (brain, intestine), toad (brain, intestine, skin), frog (brain, intestine), turtle (brain, intestine), lizard (brain, intestine, skin) and mouse (spinal cord). RIA alone was performed in extracts from branchiostoma and cricket. The concentrations of SP-LI in brain, spinal cord and intestine of different submammalian species except branchiostoma brain and intestine and turtle brain, were in a similar range (2.1–5.3 fmol/mg in the brain, 0.2–2.0 fmol/mg in the spinal cord, 0.3–4.2 fmol/mg in the intestine). In the turtle brain, extremely high SP-LI concentrations (210 fmol/mg) were found, whereas brain and intestine of branchiostoma contained very little SP-LI (0.1 fmol/mg). In the skin of different species, SP-LI concentrations varied from 0.04 fmol/mg (trout) to 2.0 fmol/mg (lizard). In the cricket, high SP-LI concentrations were found in the cerebral ganglion (15 fmol/mg protein) and in the subesophageal ganglion (27 fmol/mg protein). HPLC analysis of extracts showed that all tissues investigated contained a substance which co-eluted with synthetic SP, and in most tissues a peak was present which co-eluted with SP sulfoxide. Only in mouse spinal cord, trout brain and hagfish brain were these the only peaks. All other tissues contained, however, heterogeneous SP-LI with a different degree of heterogeneity, i.e., a different number of separated HPLC peaks. The highest number of SP-immunoreactive peaks was found in the lizard (i.e., at least 16 peaks separated by HPLC in the lizard brain). In conclusion, all submammalian species investigated seem to contain SP with the mammalian amino acid sequence or a very closely related structure. Most of these species, however, contain the genetic information to express a variety of structurally related peptides.

Partial characterization of immunoreactive substance P in the rat pituitary gland

Two distinct carboxy-terminus-directed anti-substance P (SP) sera (R-1C and R-6G) were used to characterize immunoreactive SP (I-SP) in acetic acid extracts of anterior pituitary (AP) and posterior pituitary (PP) glands of adult male rats. The tissue concentrations of I-SP measured by R-1C and R-6G were comparable. The contents of I-SP were 600–1150 pg/AP and 25–52 pg/PP. I-luteinizing hormone releasing hormone and I-somatostatin (I-SOM) were undetectable in AP extracts, but PP extracts contained the equivalents of 325–785 pg I-SOM/gland. Serial dilutions of AP and PP extracts produced displacement curves with both SP antisera that were parallel to the respective synthetic SP standard and hypothalamic extract displacement curves. Gel filtrations of AP and PP extracts on a Sephadex G-25 column produced I-SP peaks eluting in the same fractions as synthetic SP and hypothalamic I-SP. However, the AP I-SP profile also revealed a side peak migrating between the void volume and the major I-SP peak. Neither immunoreactive species in the AP extract were eliminated when eluted with 6.0 M guanidine HCl, a strong denaturing agent. In vitro incubation of paired anterior hemipituitaries for 30 min in the presence of a 56 mM K + concentration resulted in a significant (p<.0001), 25-fold increase in the release of I-SP into the incubation medium above the mean control value. Radiofrequency lesions placed in the median eminence-arcuate region of male rats caused a significant (p<.001) reduction of I-SP in both the AP and PP. These reductions were inversely related to the plasma prolactin values. The elevation in plasma prolactin was taken as an index of completeness of lesions. We conclude that: 1) the rat pituitary contains I-SP as assessed by its immunologic and chromatographic behavior, 2) K + depolarization is a potent stimulator of the release of AP I-SP in vitro , 3) the ME-arcuate region is important for the maintenance of pituitary I-SP levels in the rat.

Neuronal substance P in the esophagus. Distribution and effects on motor activity.

Substance P-immunoreactive nerve fibres were fairly numerous in the lower esophagus of the guinea-pig and cat but few in the pig. They were particularly numerous in the myenteric and submucosal plexuses but could be detected also in the circular and longitudinal smooth muscle and in the muscularis mucosae. Only in the cat were SP-immunoreactive cell bodies detected, albeit in low number, in the myenteric plexus. Radioimmunoassay showed that the lower part of the cat esophagus contained approximately 10 times more immunoreactive SP than the upper part and that the muscle layer contained more SP than the mucosa. Motor effects of synthetic SP were studied on segments from circular smooth muscle of cat esophagus. SP contracted the smooth muscle and enhanced the response to electrical stimulation. These effects of SP could be blocked by the specific SP antagonist (D-Pro2, D-Trp7, 9)-SP. The contractile response to electrical stimulation could be blocked by the cholinergic muscarinic blocker atropine and the opiate receptor agonist leu-enkephalin but not by the SP antagonist or by adrenergic blockers. Hence, the results suggest that cholinergic neurons innervate the circular smooth muscle, and that opiate receptor agonists suppress transmission in these neurons. Neuronal SP in the esophagus may serve to enhance the contractile responses of esophageal smooth muscle.

Substance P in human cord blood and its degradation by placenta in vitro.

Plasma immunoreactive substance P (iSP) was measured by radioimmunoassay in 12 paired samples of maternal and cord blood, and in placental extracts. The mean plasma iSP concentration in the cord vein was 42.5 pg/ml, as compared to 77.3 pg/ml in the maternal peripheral vein plasma. There was no difference in the mean iSP concentration in the cord vein and artery. Although no iSP was detected in placental tissue, the placenta could not be excluded as the source of iSP in cord blood in view of the rapid degradation of synthetic SP by the placental in vitro.

Activities of sulfated polysaccharides in the liberation of lipoprotein lipase into the blood and inhibition of its activity.

Using synthetic sulfated polysaccharides (SP's) of relatively low molecular weight, the effects of SP's on lipoprotein lipase [EC 3.1.1.3] (LPL) were examined. (1) The activities of synthetic SP's in the liberation of LPL are proportional to their activities for the inhibition of the LPL activity. (2) The activities of these SP's in the liberation of LPL both in vivo and in vitro, and for the inhibition of the LPL activity are proportional to their sulfate contents and molecular weights. (3) The chemical nature of the repeating a sugar units and the type of glycosidic linkage in synthetic SP's do not appreciably influence their activities in the liberation of LPL or for the inhibition of the LPL activity. (4) Unlike synthetic SP's, heparin has a specific effect on the liberation of LPL only in vivo. (5) The release of LPL from adipose tissue in vitro increases with increase in the ionic strength of the incubation medium. (6) The mechanism whereby SP's liberate LPL into the blood stream is discussed on the basis of these results.