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PubMed1994

Selective precipitation of interleukin-4 using hydrophobic ion pairing: a method for improved analysis of proteins formulated with large excesses of human serum albumin.

In order to ensure the stability of protein pharmaceuticals, human serum albumin (HSA) is often added as an excipient, frequently in large excess. This makes chromatographic analysis of the stability of the active protein difficult. In the case of interleukin-4 (IL-4), separation from HSA can be achieved to some degree by size exclusion chromatography, but some HSA co-elutes with the IL-4. Hydrophobic ion pairing provides a method for selective precipitation of IL-4 from HSA. Hydrophobic ion pairing involves the electrostatic interaction of ionic detergents with oppositely charged polypeptides. Even when HSA is present in fifty-fold excess (w/w), the resulting precipitate contains greater than 70% of the IL-4. Selective precipitation with SDS produces enhancements in IL-4 over HSA of more than 2000-fold. This approach permits subsequent facile analysis of IL-4 by conventional reverse phase HPLC.

Detergents↗
PubMed2003

Total parenteral nutrition associated crystalline precipitates resulting in pulmonary artery occlusions and alveolar granulomas.

This case report describes total parenteral nutrition (TPN) -associated crystalline precipitates occluding the pulmonary artery branches in a Crohn's disease patient who survived. These precipitates caused focal vascular disruptions and alveolar granulomas. High-resolution CT (HRCT) scan demonstrated a diffuse ground-glass appearance. Pulmonary function tests showed severe ventilatory defects, arterial hypoxemia, and decreased oxygen saturations. Energy dispersive x-ray analysis (EDAX) of the patient's lung biopsy and expectorant demonstrated similar patterns, supporting crystal migration into the alveoli. Treatment included broad-spectrum antibiotics, anticoagulation, corticosteroids, and daily pulmonary toilet. The patient required continuous supplemental oxygen for two months and then was able to use it intermittently. This patient survived widespread pulmonary vascular occlusions secondary to precipitation and crystallization of TPN solution, with moderately severe residual deficits in exercise tolerance and chest x-ray abnormalities. This case underscores the importance of surveillance and recognition and of TPN-associated complications by health care workers.

Adult↗
PubMed2000

Precipitating factors and therapeutic outcome in epilepsy with generalized tonic-clonic seizures.

OBJECTIVES: The aim of the study was to evaluate the influence of precipitating factors and therapy on the outcome of epilepsy with generalized tonic-clonic seizures. PATIENTS AND METHODS: Retrospective analysis of data from 34 patients (mean age at seizure onset 19 years; mean duration of follow-up 9.2 years) suffering from epilepsy of either cryptogenic or remote symptomatic (n = 19), or idiopathic (n = 15) etiology. The total number of seizures in all patients was 146. RESULTS: Without treatment 97 seizures manifested during 90.5 years without treatment (1.07 seizures/year), during treatment with carbamazepine or valproate 49 seizures occurred within 224 years (0.2 seizures/year). The frequency of seizures was significantly lower during treatment. Precipitating factors were found in relation to 31% of seizures in patients with remote symptomatic or cryptogenic epilepsy, and for 51% of seizures in patients with idiopathic epilepsy. CONCLUSIONS: There was a low frequency of seizures in patients with generalized tonic-clonic seizures. Precipitating factors are common. Antiepileptic drug treatment is effective.

Adolescent↗
PubMed2002

Effect of face velocity and the nature of aerosol on the collection of submicrometer particles by electrostatic precipitator.

Despite the electrostatic collection of aerosol particles as one of the most widely used air cleaning methods, there has not been sufficient amount of effort devoted to investigate its performance in the full range of operating conditions. This paper reports results of the tests of a two-stage electrostatic precipitator (ESP) conducted in the particle size range of 0.018-1.2 microns over a range of flow rates using NaCl and Environmental Tobacco Smoke (ETS) test aerosols. The total collection efficiency of the precipitator was found to increase with an increase in the count median diameter (CMD) of the particles, to have polynomial dependence on flow rate and no significant dependence on the type of test aerosol. The fractional efficiency of the precipitator was found to be dependent on flow rate. However, the 'critical' particle size of about 1.2 microns was found to exist when the fractional collection efficiency becomes independent of flow rate. For submicrometer particles, the collection efficiency was found to be independent of particle size at flow rates below 560 l/s. A minimum in the efficiency was observed in the 0.1-0.45 micron particle size range and for particles smaller than about 0.02 micron.

Aerosols↗
PubMed2003

Decoupling of erosion and precipitation in the Himalayas.

The hypothesis that abrupt spatial gradients in erosion can cause high strain rates in active orogens has been supported by numerical models that couple erosional processes with lithospheric deformation via gravitational feedbacks. Most such models invoke a 'stream-power' rule, in which either increased discharge or steeper channel slopes cause higher erosion rates. Spatial variations in precipitation and slopes are therefore predicted to correlate with gradients in both erosion rates and crustal strain. Here we combine observations from a meteorological network across the Greater Himalaya, Nepal, along with estimates of erosion rates at geologic timescales (greater than 100,000 yr) from low-temperature thermochronometry. Across a zone of about 20 km length spanning the Himalayan crest and encompassing a more than fivefold difference in monsoon precipitation, significant spatial variations in geologic erosion rates are not detectable. Decreased rainfall is not balanced by steeper channels. Instead, additional factors that influence river incision rates, such as channel width and sediment concentrations, must compensate for decreasing precipitation. Overall, spatially constant erosion is a response to uniform, upward tectonic transport of Greater Himalayan rock above a crustal ramp.

Journal Article↗
PubMed1997

Attenuation of precipitated morphine withdrawal symptoms by acute i.c.v. administration of a group II mGluR agonist.

1. We previously showed that chronic i.c.v. antagonism of metabotropic glutamate receptors (mGluRs) concurrently with s.c. morphine significantly attenuated precipitated withdrawal symptoms. Conversely, acute i.c.v. injection of a selective group II mGluR antagonist just before the precipitation of withdrawal exacerbated abstinence symptoms. 2. In the present study, we showed that acute i.c.v. administration of the non-selective mGluR agonist 1-aminocyclopentane-1,3-dicarboxylic acid ((1S,3R)-ACPD), as well as the group II selective agonist (2S,1'R,2'R,3'R)-2-(2'.3'-dicarboxycyclopropyl)glycine (DCG-IV), significantly attenuated the severity of precipitated withdrawal symptoms. 3. From these results we hypothesize that chronic opioid treatment may indirectly induce a desensitization of group II mGluRs, which contributes to the development of dependence.

Animals↗
PubMed1996

Precipitation flow injection immunoassay for human immunoglobulin G.

The development of a precipitation flow injection immunoassay is described. This approach is based on the immunoprecipitin reaction, whereby the precipitate formed by binding of the sample antigen (HIgG) to fluorescein-labelled antibodies is retained on a filter built in on-line in a flow-injection system. After dissolving the precipitate with sodium hydroxide solution the liberation of fluorescein-labelled antibodies results in a fluorescence signal that is directly proportional to the concentration of HIgG. The instrumental set-up is very simple and fully automated. One assay cycle takes about 10 min. The RSD ranged between 1 and 3%, depending on concentration. The detection limit was about 140 fmol. The recovery from spiked serum samples was between 96 and 102%.

Automation↗
PubMed2003

Pesticide concentrations in air and precipitation in the Netherlands.

Atmospheric deposition may be an important source of persistent organic compounds (POP) and pesticides for the Dutch coastal and inland waters. Current estimates of the atmospheric input have been made using atmospheric dispersion models. The uncertainty is however large. A project was defined with the aim to assess the input on the basis of measurements. For a period of two years (1999-2001) a monitoring network was operated. At eighteen stations, located across the whole country, air and precipitation samples were taken on a weekly and monthly basis. In these samples the concentrations of pesticides, PCB's and PAH's were determined. Up to 50 different pesticides were observed in precipitation and air. The concentration of 17 of these in precipitation exceeded the maximum permissible level for surface water and 22 exceeded the standard for drinking water of 100 ng l(-1). The input from the atmosphere to Dutch inland waters appeared to be as large as the input of pesticides by other sources such as spray drift. Model calculations were also carried out to identify the sources of these compounds. The occurrence of atrazine could be related to emissions outside the Netherlands.

Air Pollutants↗
PubMed1967

Fractionation of the chymotryptic precipitate of Bombyx mori silk fibroin.

1. A solution of Bombyx mori silk fibroin was digested with chymotrypsin. Amino acid analyses of the chymotryptic precipitate showed in addition to the main constituents Gly, Ala, Ser and Tyr, very small amounts of Lys, His, Arg, Asp, Thr, Glu, Pro, Cys, Val, Met, Ile, Leu, Phe and Trp. 2. A stable solution of the chymotryptic precipitate in 6m-urea was obtained by dialysing a solution in 50% (w/v) lithium thiocyanate against 6m-urea. 3. The dinitrophenylated chymotryptic precipitate in 6m-urea was fractionated by gel filtration and by ion-exchange chromatography. On Dowex 1 (X2), a main fraction I(d) and three further fractions with different amino acid compositions and molecular weights were obtained. 4. Specific rearrangement and fission of the bonds involving the serine nitrogen atoms of fraction I(d) and fractionation of the resulting mixture by gel filtration yielded five fractions. Two of these fractions had the compositions DNP-Ser-(Gly(6),Ala(4),Ser) and DNP-Ser-(Gly(4),Ala(2) or Ala(3),Ser) and are presumably double repeating units according to the proposed formula of Lucas, Shaw & Smith (1957), namely [Ser-Gly-(Ala-Gly)(n)](2), for n values of 2 and 1 respectively.

Amino Acids↗
PubMed1998

Risk of recurrent venous thromboembolism in patients with the factor V Leiden (FVR506Q) mutation: effect of warfarin and prediction by precipitating factors. East Anglian Thrombophilia Study Group.

Three cohorts of patients with the factor V Leiden mutation were recruited independently (heterozygotes, homozygotes and combined thrombophilia). The antithrombotic efficacy of oral anticoagulation and the predictive value for recurrence of an idiopathic as opposed to a precipitated first event were determined. Idiopathic first events occurred at an older age than precipitated events (43 v 26 years, LR = 23.31, P < 0.001). None of the patients had a recurrent event while on warfarin but the median time to recurrence after stopping warfarin was 9 years (95% CI 0.7-17.3 years). The time to recurrence was shorter when the first event was idiopathic as opposed to precipitated (3.5 v 13 years, LR = 4.76, P = 0.029). A calculation of benefit to risk of oral anticoagulation with a target INR of 2.5 does not support the use of long-term therapy in all patients with the factor V Leiden mutation following a first thrombotic event.

Adolescent↗
PubMed1998

Evidence that the ubiquitin proteolytic pathway is involved in the degradation of precipitated globin chains in thalassaemia.

Ultrastructural immunocytochemical studies were performed on sections of bone marrow from three patients with beta-thalassaemia major and two patients with haemoglobin H (HbH) disease. Some sections were reacted with either a polyclonal or a monoclonal anti-human-ubiquitin antibody and the reaction visualized using a gold-labelled secondary antibody. The inclusions of precipitated globin chains found within the erythropoietic cells of all five patients reacted much more strongly than the surrounding inclusion-free cytoplasm with both of the anti-ubiquitin antibodies, indicating that the precipitated globin chains were ubiquitinated. A non-specific reaction between the anti-ubiquitin antibodies and the inclusions was excluded by demonstrating that various other antibodies, including a polyclonal anti-human cathepsin D antibody, did not react with the inclusions. The data suggest that the ubiquitin proteolytic pathway is involved in the degradation of precipitated globin chains in alpha- and beta-thalassaemia.

Cathepsin D↗
PubMed2001

Transforming growth factor beta-1 stimulates articular chondrocyte elaboration of matrix vesicles capable of greater calcium pyrophosphate precipitation.

Objective To determine the role of transforming growth factor beta1 (TGFbeta) in early calcium pyrophosphate formation by measuring its effects on articular chondrocyte matrix vesicle (MV) formation, specific activity of the inorganic pyrophosphate(PPi)-generating enzyme nucleoside triphosphate pyrophospho-hydrolase (NTPPPH) and biomineralization capacity. Methods MV elaborated from mature porcine chondrocyte monolayers+/-TGFbeta were compared for protein content, NTPPPH activity, and ATP-dependent biomineralization. Precipitation of calcium pyrophosphate mineral phases by MV was determined by a radiometric assay and by Fourier transform infrared spectroscopy (FTIR). Results MV from monolayers exposed to TGFbeta were enriched in NTPPPH activity compared to MV from control monolayers (P< 0.01) and precipitated more calcium/mg MV protein than controls (P</= 0.01). FTIR spectra of mineral generated by monolayer-elaborated MV were consistent with poorly crystalline CPPD. Conclusions TGFbeta is capable of increasing the capacity of articular chondrocyte-derived MV to generate PPi via NTPPPH and precipitate calcium in the form of CPPD mineral. These data support the concept that this growth factor plays a key role in cartilage matrix CPPD deposition.

Animals↗
PubMed2002

Idiopathic paroxysmal kinesigenic choreoathetosis: precipitation of attacks by vestibular stimulation.

A 24-year-old woman presented with a 3.5-year history of paroxysmal dystonia that was precipitated by sudden movement, especially when she started to walk. It was characterised by shrugging of shoulders, flexion of the neck and thoracic spine, and stiffness of the right leg followed by falls. Each attack lasted for less than 5min. Inadequate sleep and stress were exacerbating factors. There was no similar family history. Physical examination and investigations were normal. The following manoeuvres that caused vestibular stimulation precipitated attacks: turning her head from side to side while standing still, sitting still on a rotating chair and an ice-water caloric test. She had partial responses to phenytoin and levodopa, and a good response to haloperidol. Vestibular stimulation as a precipitating factor in paroxysmal kinesigenic choreoathetosis has not been reported previously.

Adult↗
PubMed2003

Effects of uncontrolled particulate matter release on precipitation under warfare conditions.

This study has shown theoretical, observed and experimental evidence of pollutants released, transported and deposited during the Kosovo conflict in 1999 and their effects on precipitation in Serbia. The greatest bombardment of the chemical industry, oil refineries and fuel storage in Serbia which occurred during April, resulted in releases of many hazardous, toxic and cancerogenic substances. The number of April's days with precipitation greater or equal to 0.1 mm in 1999 are compared to those in the period from 1961 to 1990 registered at thirty meteorological stations in Serbia and especially at the Belgrade-Observatory station in the period from 1888 to 1995. The maximums of days with precipitation greater or equal to 0.1 mm were at the wider Belgrade area and at the central and southwestern parts of Serbia during April 1999. This is confirmed by using the Eta trajectory analysis.

Aerosols↗
PubMed2004

Tubular precipitation and redox gradients on a bubbling template.

Tubular structures created by precipitation abound in nature, from chimneys at hydrothermal vents to soda straws in caves. Their formation is controlled by chemical gradients within which precipitation occurs, defining a surface that templates the growing structure. We report a self-organized periodic templating mechanism producing tubular structures electrochemically in iron-ammonium-sulfate solutions; iron oxides precipitate on the surface of bubbles that linger at the tube rim and then detach, leaving behind a ring of material. The acid-base and redox gradients spontaneously generated by diffusion of ammonia from the bubble into solution organize radial compositional layering within the tube wall, a mechanism studied on a larger scale by complex Liesegang patterns of iron oxides formed as ammonia diffuses through a gel containing FeSO(4). When magnetite forms within the wall, a tube may grow curved in an external magnetic field. Connections with free-boundary problems in speleothem formation are emphasized.

Journal Article↗
PubMed1995

Osmotic effectors and DNA structure: effect of glycine on precipitation of DNA by multivalent cations.

We have investigated the effect of glycine (an organic osmolyte) on DNA precipitation induced by spermine4+, spermidine3+ and Tb3+ addition, using circular dichroism (CD), UV spectroscopy (UV), and electric linear dichroism (ELD) techniques. DNA precipitation by the three compounds is perturbed by glycine: more spermine4+, spermidine3+ and Tb3+ must be added to obtain the same extent of precipitation as compared to the behaviour in absence of this organic osmolyte. It seems that glycine has a general effect on the DNA environment. Calculations based on experimental results and Manning's counterion condensation theory show that glycine could modify the electrostatic environment of DNA as a consequence of a change in dielectric constant.

Animals↗
PubMed2005

Laboratory and pilot-scale phosphate and ammonium removal by controlled struvite precipitation following coagulation and flocculation of swine wastewater.

To reduce the suspended solids load to a trickling filter installation, raw swine effluent was pre-treated with ferric chloride and a cationically charged polyacrylamide coagulant resulting in unexpected struvite accumulation downstream of this post-separation process. Using this pre-treated swine manure, struvite precipitation studies were carried out as a function of pH at laboratory and pilot batch and continuously operated scales. An optimal reaction time of 30 min was established for struvite precipitation in the pre-treated swine wastewater at pH 8.5, minimizing the co-precipitation of interfering minerals. Ferric chloride addition resulted in magnesium solubilization, such that no external additional source of magnesium was required for struvite formation. Aeration alone did not result in significant pH increases, so base addition was required for pH adjustment. X-ray diffraction revealed that the only crystalline phase produced was struvite. Removal of phosphate and ammonium attained 98% and 17% respectively in laboratory scale experiments. At the pilot-scale, removal attained 99% and 15% of phosphate and ammonium in both batch and continuously HRT = 1h) operated reactors.

Animals↗
PubMed2003

Antagonist-precipitated heroin withdrawal under anaesthetic prior to maintenance naltrexone treatment: determinants of withdrawal severity.

This study sought to characterize antagonist-precipitated heroin withdrawal during and immediately following anaesthesia and to identify the determinants of withdrawal severity and duration in 48 dependent heroin users. Objective withdrawal signs decreased significantly with each naloxone bolus administered under anaesthetic. The cost (amount) of the final heroin administration and the number of hours between last heroin use and commencement of anaesthesia were significant, independent predictors of the severity of withdrawal symptomatology. While 83% (40/48) of participants completed withdrawal according to objective criteria and commenced maintenance naltrexone treatment, almost half (22/48) were unable to commence naltrexone on the day of the procedure due to residual withdrawal signs. Fourteen of these 22 participants subsequently commenced naltrexone (median number of days between admission and commencement of naltrexone was 2, range 1 - 6) while eight left treatment prior to initiation of naltrexone. Significantly fewer of those with more severe withdrawal signs during anaesthesia commenced naltrexone (40% vs. 60%). While the severity and duration of withdrawal symptomatology may be moderated by encouraging participants to reduce (or cease) heroin use close to the time of withdrawal, for a substantial proportion of participants in this study, heroin withdrawal by this antagonist-precipitated procedure was neither rapid nor painless. [Ali R, Thomas P, White J, McGregor C, Danz,C, Gowing L, Stegink A, Athanasos P. Antagonist-precipitated heroin withdrawal under anaesthetic prior to maintenance naltrexone treatment: determinants of withdrawal severity.

Adolescent↗