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PubMed2000

Previous experience of withdrawal from chronic diazepam ameliorates the aversiveness of precipitated withdrawal and reduces withdrawal-induced c-fos expression in nucleus accumbens.

Flumazenil (20 mg/kg, i.p.)-precipitated withdrawal from chronic treatment with diazepam (DZP, 15 mg/kg, s.c. in sesame oil for 21 days) resulted in a decreased seizure threshold to the convulsant, pentylenetetrazole (PTZ), infused into the tail vein; withdrawal from 21-day chronic diazepam treatment, interspersed with two periods of drug withdrawal, resulted in a greater decrease in convulsant threshold. A separate experiment showed that consumption of a sucrose solution immediately prior to precipitated withdrawal resulted in a decreased subsequent consumption of the sucrose solution; no such evidence of a conditioned taste aversion (CTA) was seen in mice given prior experience of withdrawal. Thus, prior experience of withdrawal enhanced the effects of a subsequent precipitated withdrawal in increasing seizure sensitivity, but weakened the ability of this withdrawal to serve as an aversive unconditioned stimulus (US). The weakening of the aversive properties of precipitated withdrawal may reflect habituation to the withdrawal stimulus, and was accompanied by a loss of the ability of withdrawal to induce c-fos expression in the shell of the nucleus accumbens, an area sensitive to both novel, and stressful, as well as rewarding stimuli.

Amygdala↗
PubMed1984

Chronic paroxysmal hemicrania. VII. Mechanical precipitation of attacks: new cases and localization of trigger points.

Two new chronic paroxysmal hemicrania patients are described. In both, attacks can be precipitated mechanically by applying firm manual pressure to certain sensitive points on the neck, i.e. in the C2 area, in the transverse processes of the C4-C5 vertebrae, or beneath the posterior part of the skull on the symptomatic side. The most sensitive area seems to be the transverse process of C4-C5. Susceptibility to this type of attack is dependent on the flow of spontaneous attacks; attacks are easily precipitated in a phase with multiple spontaneous attacks, but are not readily precipitated otherwise. Under indomethacin protection, local tenderness is clearly diminished and attacks cannot be precipitated.

Adult↗
PubMed2003

Dopamine-dependent increases in phosphorylation of cAMP response element binding protein (CREB) during precipitated morphine withdrawal in primary cultures of rat striatum.

Chronic morphine leads to compensatory up-regulation of cAMP signaling pathways in numerous brain regions. One potential consequence of up-regulated cAMP signaling is increased phosphorylation of cAMP response element binding protein (CREB), a transcription factor that may regulate neuroadaptations related to morphine dependence. Altered gene expression within the nucleus accumbens (NAc), a ventral component of the striatum that receives substantial dopaminergic input, may play a role in some of the motivational aspects of opiate withdrawal. To determine if morphine withdrawal leads to increased CREB phosphorylation in striatal tissues, we examined the effects of naloxone-precipitated morphine withdrawal on CREB phosphorylation in primary cultures of rat striatal neurons. Precipitated morphine withdrawal was associated with enhanced dopamine-, SKF 82958 (D1 receptor agonist)-, and forskolin-induced CREB phosphorylation. During precipitated withdrawal, D1 receptor-mediated CREB phosphorylation was dependent on cAMP-dependent protein kinase (PKA). Precipitated withdrawal also led to up-regulation of c-fos mRNA in response to SKF 82958. CREB protein levels were not altered by acute or chronic morphine. These results suggest that D1 receptor-mediated signal transduction is enhanced during morphine withdrawal. Furthermore, they are consistent with in vivo evidence suggesting that increased CREB activation in portions of the striatum (e.g. the NAc) is related to dysphoric states associated with drug withdrawal.

Animals↗
PubMed2004

Regional crustal thickness and precipitation in young mountain chains.

Crustal thickness is related to climate through precipitation-induced erosion. Along the Andes, the highest mountains and thickest crust (approximately 70 km) occur at 25 degrees south, a region of low precipitation. Westerly winds warm passing over the Atacama Desert; precipitation is modest in the High Andes and eastward over the Altiplano. Severe aridity, hence low erosion rates, helps to account for the elevated volcanogenic contractional arc and high, internally draining plateau in its rain shadow. Weak erosion along the north-central arc provides scant amounts of sediment to the Chile-Peru Trench, starving the subduction channel. Subcrustal removal might be expected to reduce the crustal thickness, but is not a factor at 25 degrees south. The thickness of the gravitationally compensated continental crust cannot reflect underplating and/or partial fusion of sediments, but must be caused chiefly by volcanism-plutonism and contraction. Contrasting climate typifies the terrain at 45 degrees south where moisture-laden westerly winds encounter a cool margin, bringing abundant precipitation. The alpine landscape is of lower average elevation compared with the north-central Andes and is supported by thinner continental crust (approximately 35 km). Intense erosion supplies voluminous clastic debris to the offshore trench, and vast quantities are subducted. However, the southern Andean crust is only about half as thick as that at 25 degrees south, suggesting that erosion, not subcrustal sediment accretion or anatexis, is partly responsible for the thickness of the mountain belt. The Himalayas plus Tibetan Plateau, the Sierra Nevada plus Colorado Plateau, and the Japanese Islands exhibit analogous relationships between crustal thickness and climate.

Journal Article↗
PubMed1979

Zone precipitation chromatography: its use in the isolation of different collagen types.

Zone Precipitation Chromatography is a useful technique for the initial isolation of the different collagen types in their native configuration. Small quantities of collagen mixtures can be rapidly separated into different collagen types with a relatively high degree of purity, based upon stained protein patterns on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) slab gels. In the commonly used bulk salt preparative method for isolating the different collagens, 50 mg of starting material was needed. Three days were required to complete the procedure. The stained protein patterns on SDS-PAGE slab gels showed about 25% contamination with the bulk purified Type III fraction and 20% contamination with the bulk purified type AB collagen. With Zone Precipitation Chromatography 5 mg of starting material was used and in less than 4 hours the mixture was separated with Types III and AB fractions showing less than 10% contamination from other collagen types. The technique is patterned after the Zone Precipitation method reported by Porath seventeen years ago and utilizes a step-wise sodium chloride gradient to precipitate and redissolve the collagens, eluting from the interbead spaces of a molecular sieve column.

Animals↗
PubMed2006

Stable isotope composition of daily and monthly precipitation in Zagreb.

Stable isotopic compositions (delta2H and delta18O) of daily precipitation collected in the period from October 2002 to March 2003 and monthly precipitation in the period from 2001 to 2003, as well as the corresponding meteorological data (temperature, amount of precipitation), all collected in Zagreb, Croatia, are presented. delta2H and delta18O values, both daily and monthly, show large variations due to large temperature variations and the different origin of the air masses. Variations are larger for daily samples than for composite monthly samples. Good correlation of delta18O with temperature is obtained for both types of samples. On the basis of the correlation between delta2H and delta18O, the local meteoric water line is close to the global meteoric water line. Deuterium excess of both daily and monthly precipitation indicates that in the Zagreb area, the influence of air masses from the Mediterranean area prevails in the autumn period.

Air Movements↗
PubMed2004

Psychosocial stressors that precipitate dissociative trance disorder in Singapore.

OBJECTIVE: To study the psychosocial stressors that precipitate dissociative trance disorder (DTD) and to identify predictors of DTD. METHOD: We conducted semistructured interviews in which detailed information was obtained for 58 cases diagnosed with DTD at a psychiatric hospital in Singapore. A comparison group of 58 patients who received treatment at the same hospital for major depression (MD) were also interviewed, using the same instrument. RESULTS: While 100% of the DTD group described at least one psychosocial stressor, only 80% of the MD group did so. Common stressors for the DTD group include problems with military life (38%), conflicts over religious and cultural issues (38%), and domestic disharmony and marital woes (24%). Conflicts over religious and cultural issues seemed to be important in the precipitation of DTD but not in the precipitation of MD (p < 0.001). Logistic regression reveals that the following are positive predictors for DTD: conflicts over religious and cultural issues; prior exposure to trance states; and being a spiritual healer or his/her assistant. CONCLUSIONS: An understanding of the precipitating psychosocial stressors that overwhelmed the patient's coping abilities would have implications for treatment and enable the clinician to devise strategies for intervention and prevention.

Adolescent↗
PubMed1980

Localization of Ca++-containing antimonate precipitates during mitosis.

Intracellular bound Ca++ has been localized throughout mitosis and cytokinesis in two plant species by means of in situ precipitation with potassium antimonate and electron microscope visualization. Identification of Ca++ as the major cation precipitated was made by comparing solubility properties in water, EDTA, and EGTA of the intracellular deposits with respect to those of K+-, Mg++-, and Ca++-antimonate standards. In spermatogenous cells of the water fern, Marsilea vestita, and stomatal complex cells of barley, Hordeum vulgare, antimonate deposits have been found associated with the endoplasmic reticulum (ER), vacuoles, euchromatin/nucleoplasm, and mitochondria. The last contain a much higher density of precipitates in Marsilea than in Hordeum. Dictyosomes and the nuclear envelope of Marsilea also contain antimonate deposits, as do the plasmalemma, cell wall, and phragmoplast vesicles of Hordeum. Microtubule-organizing centers such as kinetochores and the blepharoplast of Marsilea do not stain. In spite of differences in associated antimonate between certain organelles of the two species, the presence of antimonate aong the ER throughout the cell cycle is common to both. Of particular interest are those precipitates seen along the tubules and cisternae of the extensive smooth ER that surrounds and invades the mitotic spindle in both species. The ability to bind divalent cations makes the mitotic apparatus (MA)-associated ER a likely candidate for regulation of free Ca++ levels in the immediate vicinity of structural components and processes that are Ca++-sensitive and proposed to be Ca++-regulated.

Anaphase↗
PubMed1956

Glomerular lesions and the nephrotic syndrome in rabbits given saccharated iron oxide intravenously; with special reference to the part played by intracapillary precipitates in the pathogenesis of the lesions.

Intravascular precipitates, comprised at least in part of iron, formed regularly in rabbits given one or more injections of a saccharated iron oxide preparation intravenously, and these lodged in numerous capillaries throughout the body, particularly those of the lungs and kidneys. Large numbers of the brownish precipitates remained in the capillaries of the renal glomeruli during the first few days following injection of the iron, but most of them disappeared after 5 to 7 days, with only moderate amounts of brown pigment remaining in the endothelial cells of the renal glomeruli. Signs of acute injury of the glomerular tufts-namely) pyknosis of some of the endothelial cells, margination of leukocytes within the glomerular capillaries, and slight proliferation of the epithelial cells-also developed some 5 to 7 days following injection of the iron, along with marked proteinuria, which proved transitory if no further injections were given. When the iron preparation was given repeatedly over prolonged intervals, however, the proteinuria persisted and became extreme, and hypoproteinemia developed, often with hypercholesterolemia and transitory edema as well. Histological studies of the kidneys of rabbits manifesting the nephrotic syndrome, as just described, disclosed that virtually all the renal glomeruli were greatly altered, mainly owing to proliferation of the epithelial cells, together with some fibrosis and atrophy. Some of the rabbits having marked proteinuria and other functional changes eventually developed azotemia following repeated injections of the iron, and several of them lost weight and died; the renal glomeruli of these animals showed changes like those just described, but the alterations were more extensive. Considered together, the findings provide evidence that the intravascular precipitates first occluded the glomerular capillaries for a period of several days following injection of the iron and then largely disappeared from them just prior to the development of morphologic signs of glomerular injury and proteinuria. Hence the possibility was considered that the intracapillary precipitates might have produced acute injury to the walls of the glomerular capllaries through the agency of anoxia. But it is plain that the findings of the present study do not disclose the essential nature of the anatomical change responsible for the proteinuria, or the means whereby this was produced. The findings as a whole were briefly considered in relation to the pathogenesis of the nephrotic syndrome as it occurs naturally in human beings.

Animals↗
PubMed1983

Precipitating antigen-antibody systems are required for the formation of subepithelial electron-dense immune deposits in rat glomeruli.

This study was conducted to determine whether multivalent, precipitating antigens are required for formation of subepithelial electron-dense immune deposits in glomeruli. 2-nitro-4-azidophenyl (NAP) was conjugated with variable density to human serum albumin (HSA) to yield nonprecipitating (NAP3.1 X HSA and NAP11.4 X HSA) and precipitating (NAP19.7 X HSA) antigens with antibodies to the hapten. These antigen preparations were cationized with ethylene diamine to enhance deposition in renal glomeruli due to interaction with the fixed negative charges in the glomerular capillary wall. Following injection into the left renal artery of rats these antigens alone persisted in the glomeruli for a relatively short time by immunofluorescence microscopy. When antibodies to NAP were injected intravenously after the antigen injection, the nonprecipitating antigens and antibodies were detectable in the glomeruli by immunofluorescence microscopy up to 8 h, comparable to antigen alone. Electron-dense deposits were not formed in these glomeruli. In contrast, when the precipitating antigen was injected and followed by antibodies to the hapten, antigen and antibody were detected by immunofluorescence microscopy through 96 h. In these specimens electron-dense deposits were present from 40 min through 96 h and after 24 h the deposits were present only in the subepithelial area. The same results were obtained when the nonprecipitating hapten-carrier conjugates were followed with antibodies to the carrier molecule. These data indicate that the persistence of immune deposits by immunofluorescence microscopy and the formation of electron-dense deposits in the subepithelial area require a precipitating antigen-antibody system.

Animals↗
PubMed1975

Size fractionation of double-stranded DNA by precipitation with polyethylene glycol.

We show that DNA molecules of differing molecular mass are separable by selective precipitation with polyethylene glycol (PEG+.. Higher molecular mass DNA precipitates at lower PEG concentrations than lower molecular mass DNA. Double-stranded DNA can be fractionated at least in the range of 3 times 10-7 to 1 times 10-5 daltons. The effects on PEG concentration, sodium chloride concentration, DNA concentration, pH, divalent ions, precipitation time, and centrifugal force have been determined. These studies show PEG precipitation offers a size fractionation method for DNA which is convenient, of high capacity, and applicable over a wide range of conditions. However, resolution is not high and separation of two species approaches 100% only if they differ in molecular mass by at least a factor of two.

Cations, Divalent↗
PubMed1996

Transfecting mammalian cells: optimization of critical parameters affecting calcium-phosphate precipitate formation.

DNA-calcium phosphate co-precipitates arise spontaneously in supersaturated solutions. Highly effective precipitates for transfection purposes, however, can be generated only in a very narrow range of physico-chemical conditions that control the initiation and growth of precipitate complexes. The concentrations of calcium and phosphate are the main factors influencing characteristics of the precipitate complex, but other parameters, such as temperature, DNA concentration and reaction time are important as well. An example for this is the finding that almost all of the soluble DNA in the reaction mix can be bound into an insoluble complex with calcium phosphate in <1 min. Extending the reaction time to 20 min results in aggregation and/or growth of particles and reduces the level of expression. With improved protocols we gained better reproducibility and higher efficiencies both for transient and for stable transfections. Up to 60% of cells stained positive for beta-gal and transient production of secreted proteins was improved 5- to 10-fold over results seen with transfections using standard procedures. Similar improvements in efficiency (number of recombinant cell colonies) were observed with stable transfections, using co-transfected marker plasmids for selection. Transient expression levels 2 days after DNA transfer and titers obtained from stable cell lines, emerging weeks later, showed strong correlation.

Animals↗
PubMed1977

Immunochemical studies on non-precipitating guinea pig antibody produced by administration of an excessive dose of Bacillus subtilis alpha-amylase.

Administration of an excessive dose of Bacillus subtilis alpha-amylase [EC 3.2.1.1, alpha-1,4-glucan 4-glucanohydrolase] (BalphaA) induced the production of non-precipitating (non-ppt) IgG2 antibody in guinea pigs, whereas immunization with a normal dose produced precipitating (ppt) IgG1 and IgG2 antibodies. The non-ppt IgG2 antibody thus produced could be isolated from the coexisting ppt IgG2 antibody by means of the precipitin reaction at maximum precipitation. The non-ppt antibody was incapable of forming a precipitin arc with BalphaA in a conventional agar plate. In the presence of 4% polyethylene glycol (PEG), however, it formed a single arc which fused completely with those of the ppt IgG1 and IgG2 antibodies. The non-ppt antibody could not fix complement, but inhibited BalphaA activity, though with less efficiency than the ppt antibodies. These properties of the non-ppt IgG2 antibody may be due to a low affinity for BalphaA, since both gel filtration and precipitation of soluble antigen-antibody complexes with 20% PEG showed that the antibody was easily dissociable from BalphaA.

Amylases↗
PubMed1983

The late bronchus-obstructive response to bronchial challenge with pigeon faeces and its correlation with precipitating antibodies (IgG) in the serum of patients having long-term contact with pigeons.

From a total of 160 patients with allergic bronchial asthma or chronic asthmatic bronchitis, eighteen (11.3%) patients reported being regularly exposed to pigeons. In these eighteen patients, bronchial provocation tests with pigeon faeces were performed and the precipitating antibodies (IgG) in their serum against pigeon faeces and serum were estimated. Of the eighteen patients, seven (39%) demonstrated a 'late bronchus-obstructive response' to pigeon faeces. Three patients developed only an 'isolated late response' and in the other four patients the late response occurred as a part of the 'dual response'. In the seven patients with the positive late bronchial response, the precipitating antibodies in their serum to pigeon faeces were positive in five (71%) and to pigeon serum in two (28%) of them. The late skin responses to pigeon faeces were positive in five (71%) patients, the blood eosinophilia increased in six (86%) of them, a slight pyrexia occurred in two (28%) and general malaise symptoms appeared in six (86%) of them. None of these patients developed changes on the chest X-ray during the late response. The remaining eleven patients did not develop any bronchial response to pigeon faeces challenge, although in six (55%) of them the late skin responses were positive, and two (18%) had precipitating antibodies in the serum to pigeon faeces and one (9%) to pigeon serum. It is concluded that positive precipitating antibodies in the serum to pigeon faeces and serum are important parameters for detection of pigeon breeder's disease in exposed individuals, however confirmation of this diagnosis should be provided by the bronchial provocation tests.

Adolescent↗
PubMed1986

Studies of erythropoietic cells in heterozygotes and homozygotes for haemoglobin Constant Spring and in heterozygotes for both haemoglobin Constant Spring and alpha-thalassaemia 1 trait: extent of globin chain precipitation and cell cycle distribution.

Electron microscope studies revealed that the average value for the percentage of erythropoietic cell profiles containing globin chain precipitates in heterozygotes for haemoglobin Constant Spring (HbCS) was similar to that in subjects with alpha-thalassaemia 2 trait and that the average values for this parameter in homozygotes for HbCS and patients with HbCS-H disease were similar to that in individuals with HbH disease. The explanation for the finding that the presence of two alpha cs genes (in homozygotes for HbCS) caused a degree of precipitation corresponding to that seen in patients with HbH disease, who have three deleted alpha genes, rather than to that seen in individuals with alpha-thalassaemia 1 trait, who have two deleted alpha genes, is uncertain. In all the patients with HbCS studied, the majority of the inclusions of precipitated globin chains had a stellate or branching appearance and were considered to consist of beta-chains. However, in the homozygotes for HbCS and to a lesser extent in the patients with HbCS-H disease there were small but significant numbers of erythropoietic cell profiles containing multiple rounded inclusions of the type seen in the beta-thalassaemia syndromes, or both branching and multiple rounded inclusions. It is argued that these rounded inclusions probably consisted either of precipitated HbCS or beta-chains rather than alpha-chains. The distribution of erythroblasts in the different stages of the cell cycle was normal in two homozygotes for HbCS and two patients with HbCS-H disease, indicating that there was little or no cell death during the proliferative phase of erythropoiesis in either of these conditions.

Adult↗
PubMed1982

Thyrotrophin binding inhibition by anti-thyrotrophin receptor antibodies in Graves' disease which is not reflected by 1.6 M ammonium sulphate precipitates.

In ten patients with Graves' disease before, during and after treatment and three patients in remission, we have compared the TSH-binding inhibition caused by serum, 1.6 M ammonium sulphate precipitates from serum and by the fractions (19S, 7S and 4S) obtained after G-200 gel chromatography of serum and ammonium sulphate precipitates. Five out of ten patients had a positive thyrotrophin-binding inhibitor immunoglobulin (TBII) index before treatment, three of whom relapsed. The binding inhibition caused by 7S fractions from ammonium sulphate precipitates of ten untreated patients could be correlated with their TBII index (r=0.9, P less than 0.001). By contrast, the 7S fractions prepared directly from the sera of the same ten patients all showed marked TSH-binding inhibition (P less than 0.001) when compared with normal plasma 7S, and no correlation with the TBII index could be demonstrated (r=0.21, P less than 0.05). It is concluded that ammonium sulphate precipitates, which are used to calculate the TBII index, do not reflex the presence of anti-TSH receptor antibodies in serum accurately in all patients.

Adult↗
PubMed2004

Genetic variation in piñon pine, Pinus edulis, associated with summer precipitation.

Three previous reports of microgeographical variation of glycerate dehydrogenase (Gly) frequencies in piñon, Pinus edulis, established the hypothesis that Gly frequencies contribute to adaptation to heterogeneous environments, specifically to variation in soil moisture. In each of these studies, the frequency of the Gly-3 allele or of Gly-33 homozygotes was higher on dry sites than on nearby moist sites. Here we attempt to extend these observations by testing the hypothesis that Gly frequencies respond to soil moisture variation on a range-wide scale. Gly frequencies were surveyed in 11 natural populations, and the frequency of the Gly-3 allele varied from 0.27 to 0.65 among the sample sites. Elevation varied from 1650 to 3100 m, and summer precipitation, defined as precipitation from April to August, varied from 13.7 to 26.4 cm. The soil types at the collection sites were schist, quaternary volcanic or a mixture of shale and sandstone. Logistic regression revealed that Gly frequencies did not respond to either elevation or soil type, but were related to summer precipitation (P < 0.01). The correlation between summer precipitation and the frequency of the Gly-3 allele was r = -0.92 (P < 0.001). Thus, the patterns of differentiation on microgeographical scales are consistent with greater differentiation on a range-wide scale.

Carbohydrate Dehydrogenases↗
PubMed1996

The experience of precipitate labor.

BACKGROUND: Despite abundant research on psychosocial factors related to childbirth, no studies have focused on the specific phenomenon of a precipitate labor. A descriptive exploratory study was conducted to investigate this experience. METHOD: Semistructured interviews were conducted in 1992 with 11 women 3 to 4 months after they gave birth. Transcribed interviews were then analyzed using latent content analysis. RESULTS: The experience of precipitate labor was categorized in terms of physical experience (perception of labor length and contractions), psychological experience (relationship of how women perceived birth to their prenatal expectations, and emotional trajectory of disbelief, alarm panic, and relief), and external factors (support persons and hospital system). CONCLUSIONS: Understanding the experience of precipitate labor is essential before caregivers can offer appropriate support to clients. Perinatal caregivers gain valuable insight into a woman's experience by comprehending the speed, intensity, and emotional impact specific to precipitate labor.

Adult↗