SEARCH · Search PubMed

Results for “TCP”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources

PubMed1985

Vascularization of tricalcium phosphate, an artificial bone substitute: preliminary observations.

Tricalcium phosphate (TCP), a biodegradable artificial bone substitute, was used to study the following questions: i) can TCP be vascularized; ii) do ectopically placed implants have osteoinductive capacity; and iii) does vascularization affect implant resorption? Implants were placed in dogs in several areas: i) subcutaneous controls; ii) wrapped with latissimus dorsi muscle; iii) wrapped in omentum; iv) saphenous and thoracodorsal av pedicles threaded through implant. Prior to harvest, animals were given tetracycline and implants were harvested at 3, 6, and 9 weeks. Microfil was injected prior to sacrifice and specimens were xeroradiographed. Histology and computerized axial tomography were obtained. From this study, we conclude that 1) TCP can be vascularized; 2) the most effective method of vascularization was by an AV pedicle threaded through the implant; 3) vascularized implants did not have osteoinductive properties per se, and 4) in the time observed no difference in implant resorption was demonstrated between the test groups.

Animals↗

PubMed2006

Determination of chlorpyrifos and its metabolites in rat brain tissue using coupled-column liquid chromatography/electrospray ionization tandem mass spectrometry.

A method has been developed to quantify chlorpyrifos (O,O-diethyl-O-[3,5,6,-trichloro-2-pyridyl] phosphorothionate) and its metabolites chlorpyrifos-oxon (O,O-diethyl-O-[3,5,6,trichloro-2-pyridinyl] phosphate) and TCP (3,5,6,-trichloro-2-pyridinol) in rat brain tissue by coupled-column liquid chromatography/electrospray ionization tandem mass spectrometry (LC/LC/ESI-MS/MS). Rat brains were homogenized and treated by protein precipitation using ice-cold acetonitrile. The supernatant was directly injected onto the coupled-column system. Sample clean-up was achieved on a Zorbax Extend-C(18) column (2.1 x 50 mm, 5 microm) using a mobile phase of acetonitrile/water with 0.0025% formic acid (40:60, v/v). The compounds were separated isocratically on a Zorbax Eclipse XDB C(8) column (2.0 x 150 mm, 5 microm) using a mobile phase of acetonitrile/water with 0.0025% formic acid (75:25, v/v). Chlorpyrifos and chlorpyrifos-oxon were detected in positive ion mode using multiple reaction monitoring (MRM). TCP was detected in negative ion mode using precursor-to-precursor transition monitoring. The method was validated and the specificity, linearity, limit of quantitation (LOQ), precision, accuracy, stability, and recoveries were determined. Calibration curves for all three analytes yielded correlation coefficients of 0.993 or greater. The LOQs were 25.3 ng/g for chlorpyrifos and 6.3 ng/g for chlorpyrifos-oxon and TCP. All precision relative standard deviations (RSDs) were less than 16% for the LOQ and less than 11% for the other QC samples. This method was successfully applied to six rats that were injected subcutaneously with chlorpyrifos.

Animals↗

PubMed1996

Subchronic delayed neurotoxicity evaluation of jet engine lubricants containing phosphorus additives.

Synthetic polyol-based lubricating oils containing 3% of either commercial tricresyl phosphate (TCP), triphenylphosphorothionate (TPPT), or butylated triphenyl phosphate (BTP) additive were evaluated for neurotoxicity in the adult hen using clinical, biochemical, and neuropathological endpoints. Groups of 17-20 hens were administered the oils by oral gavage at a "limit dose" of 1 g/kg, 5 days a week for 13 weeks. A group of positive control hens was included which received 7.5 mg/kg of one isomer of TCP (tri-ortho-cresyl phosphate, TOCP) on the same regimen, with an additional oral dose of 500 mg/kg given 12 days before the end of the experiment. A negative control group received saline. Neurotoxic esterase (NTE) activity in brain and spinal cord of hens dosed with the lubricating oils was not significantly different from saline controls after 6 weeks of treatment. After 13 weeks of dosing, NTE was inhibited 23 to 34% in brains of lubricant-treated hens. Clinical assessments of walking ability did not indicate any differences between the negative control group and lubricant-treated hens. Moreover, neuropathological examination revealed no alterations indicative of organophosphorus-induced delayed neuropathy (OPIDN). In hens treated with the positive control, significant inhibition of NTE was observed in brain and spinal cord at both 6 and 13 weeks of dosing; this group also demonstrated clinical impairment and pathological lesions indicative of OPIDN. In conclusion, the results of the present study indicated that synthetic polyol-based lubricating oils containing up to 3% TCP, TPPT, or BTP had low neurotoxic potential and should not pose a hazard under realistic conditions of exposure.

Acetylcholinesterase↗

PubMed1993

The role of toxin-coregulated pili in the pathogenesis of Vibrio cholerae O1 El Tor.

Studies in the infant mouse cholera model have evaluated the significance of toxin-coregulated pili (TCP) in the pathogenesis of Vibrio cholerae strains of El Tor biotype. Four El Tor strains--two which produce TCP during in vitro growth and two which do not--were mutated by the insertion of an antibiotic-resistance cartridge into the tcpA gene (encoding the pilin monomer). The resulting mutants were otherwise indistinguishable from wild-type and in particular were unaltered in their sensitivity to antibody-dependent, complement-mediated bacteriolysis. All were dramatically attenuated and showed a marked impairment in terms of in vivo persistence in mixed-infection competition experiments. Virulence was restored by provision of a functional tcp operon in trans, confirming that the pathogenic potential of El Tor strains is critically dependent upon product(s) of this operon.

Animals↗

PubMed2005

Functional results of the colon J-pouch versus transverse coloplasty pouch in Heidelberg.

Within the last 20 years various achievements have been made in the treatment of rectal cancer, improving survival and quality of life of rectal cancer patients. Especially the introduction of the total mesorectal excision (TME) and the use of modern staplers, making anastomoses possible in the deep pelvis, have increased our ability to cure more and more low rectal cancers by sphincter-preserving low anterior resections. Consequently, the interest in functional results after rectal reservoir reconstruction has increased significantly. Various randomized controlled trials have shown that the colon J-pouch (CJP) as a rectal reservoir reconstruction leads to better early functional results compared to the straight coloanal anastomosis (CAA). However, 30% of the patients with CJP faced late evacuation problems, requiring the chronic use of enemas or laxatives. This rate could be decreased to 10% by shortening the limb of the CJP from 8-10 cm to 5-6 cm. The transverse coloplasty pouch (TCP) was developed to provide early functional results comparable to the CJP, while avoiding these late evacuation problems. We report the early postoperative and functional results of 106 patients undergoing low anterior resections with TCP due to rectal cancer between October 2001 and the end of September 2003. Furthermore, we report on a single-center randomized controlled trial to compare the new TCP technique with the gold standard technique of CJP, which we started in October 2002. The objectives were to compare the two pouch reconstruction techniques in terms of morbidity, mortality and functional results.

Adult↗

PubMed1990

Changes in signal transduction in Alzheimer's disease.

We studied the signal transduction system including the receptor and protein kinase C (PKC) in Alzheimer's disease (AD) brains. We used 3H-TCP as a ligand for the NMDA receptor-ion channel complex. The total concentrations of 3H-TCP binding sites were significantly reduced in AD frontal cortex. 3H-TCP binding sites spared in AD brains retained the affinity for the ligand and the reactivity to NMDA, L-glutamate, and glycine. We utilized antibodies to assess the degree of involvement of different PKC isoforms in AD. The concentration of PKC (beta II) was lower in AD particulate fractions and higher in AD cytosol fractions. Immunocytochemical studies revealed reduced numbers of anti-PKC (beta II)-immunopositive neurons. Anti-PKC (alpha) faintly stained entire plaques and surrounding glial cells. Anti-PKC (beta I) stained dystrophic plaque neurites. Anti-PKC (beta II) stained the amyloid-containing portions of plaques. These results suggest an involvement of second messenger cascades in the pathogenesis of AD in addition to neurotransmitters and their receptors.

Aged↗

PubMed1977

Mitochondrial degeneration after organic phosphate poisoning in prosimian primates.

The degenerative reaction of mitochondria to tricresylphosphate (TCP) poisoning in spinal ganglion cells of Slow Loris (Nycticebus coucang coucang) were studied with the electron microscope. In neurones of animals treated with TCP, mitochondria display various stages of alterations which confirm mitochondrial involvement in TCP poisoning. The role of degenerated mitochondria in the formation of neuronal lipofuscin is discussed. It is suggested that the lipofuscin granule is a metabolic product inherently related to mitochondrial degeneration, irrespective of the primary cause: ageing or intoxication.

Animals↗

PubMed1992

Internal exposure to organic substances in a municipal waste incinerator.

Fifty-three persons occupied in a municipal waste incinerator were examined with respect to their internal exposure to organic substances which may be produced during pyrolysis of organic matter. For this purpose the levels of benzene in blood, polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) in plasma, and mono- (MCPs), di- (DCPs), tri- (TCPs), tetra- (TCEPs) and pentachlorophenol (PCP) and hydroxypyrene in urine were determined. For control purposes, 431 men and women were examined. Significantly higher values for the workers were found for the excretion of hydroxypyrene [median (m): 0.24 vs 0.11 microgram/l; non-smokers], 2,4/2,5-DCP (m: 10.5 vs 3.9 micrograms/l) and 2,4,5-TCP (m: 1.2 vs 0.8 micrograms/l) and for the HCB level in plasma (m: 4.4 vs 2.8 micrograms/l). For the concentrations of 4-MCP and 2,3,4,6/2,3,5,6-TECP, the controls had significantly higher concentrations in urine than did the workers in the incineration plant (m: 4-MCP 1.7 vs 1.2; 2,3,4,6/2,3,5,6-TECP: 1.2 vs 0.3 micrograms/l). No significant differences between workers and controls were detected with respect to benzene in blood (m: 0.20 vs 0.28 microgram/l; non-smokers), 2,4,6-TCP and PCPs in urine (m: 0.85 vs 0.60 and 2.2 vs 2.2 micrograms/l) or the levels of PCB congeners in plasma (m: sigma 138, 153, 180: 5.6 vs 4.1 micrograms/l). The elevated levels of hydroxypyrene, 2,4/2,5-DCP, 2,4,5-TCP and HCB in biological material may be related to the incineration of the waste. These elevations, however, are very small and are of interest more from the environmental than from the occupational point of view.

Adult↗

PubMed1977

Stereotypy and hyperactivity in rats receiving ethanol and a monoamine oxidase inhibitor.

The combined administration of tranylcypromine (TCP) and ethanol to rats produced both a marked increase in general locomotion such as walking and running and the appearance of repetitive stereotyped head and trunk weaving, forepaw padding, and circling movements. Pretreatment with p-chlorophenylalanine (pCPA) abolished the stereotyped behaviors. In contrast, animals pretreated with alpha-methyl-p-tyrosine (AMPT) were virtually indistinguishable from those receiving only TCP + ethanol, except for a decrease in running behaviors. The above results are consistent with a serotonergic mediation of these specific stereotypes. The mechanisms by which TCP + ethanol might produce these effects are discussed.

Animals↗

PubMed1982

Oral self-administration of phencyclidine analogs by rhesus monkeys: conditioned taste and visual reinforcers.

Three monkeys self-administered orally-delivered phencyclidine, 1-(1-phencyclohexyl) piperidine (PCP), N-ethyl-1-phencyclohexylamine (PCE), and 1-[1-(2-thienyl)cyclohexyl]piperidine (TCP) over a wide range of concentrations (0.0156, 0.0312, 0.0625, 0.125, 0.25, and 0.5 mg/ml). Water was also available under a concurrent fixed-ratio (FR) 16 schedule. Drug deliveries were substantially higher than concurrent water deliveries at all concentrations, indicating that the three compounds functioned as effective reinforcers. Maximum liquid deliveries occurred at concentrations of 0.0625 (PCP and TCP) and 0.125 mg/ml (PCE). TCP was much shorter-acting (10-15 min) than PCP (4-6h) based on observations of severe ataxia at high concentrations. To investigate the conditioned reinforcing effects of taste, a quinine solution (0.088 mg/ml) was substituted for PCP (0.25 mg/ml) in five monkeys. Four monkeys responded for quinine in excess of water for a range of seven to over 30 sessions, while one monkey (M-R) did not show any substantial responding for quinine. With the same five monkeys (treatment order mixed), the effect of visual stimuli was tested by substituting water for PCP while retaining the visual stimuli indicating drug availability. Four monkeys showed increased responding on the side signaling drug for only 0-4 sessions, while one monkey (M-R) showed persistent responding for water on the side with drug stimuli for 29 sessions. These results indicated that taste functioned as an effective conditioned reinforcer, while visual stimuli appeared to be less effective in the oral drug self-administration paradigm.

Administration, Oral↗

PubMed1978

A thermodynamic analysis of the amorphous to crystalline calcium phosphate transformation.

A thermodynamic analysis of the precipitation of amorphous calcium phosphate (ACP) and its transformation to crystalline apatite had been made. A nearly constant ion product, over a wide variety of conditions, was obtained for a tricalcium phosphate (TCP)-like phase suggesting that the molecular unit which governs the solubility of ACP may be similar in composition to TCP. The introduction of 10% acid phosphate into the formula for the TCP ion product improves the fit of experimental data and results in an invariant ion product. The stability of ACP in solution was found to be dependent upon its thermodynamic instability with respect to an octacalcium phosphate (OCP)-like phase. The dependence of the induction period for the amorphous to crystalline transformation upon the pH and the Ca/P ratio of the solution is best explained by the assumption that an OCP-like phase is initially nucleated on the surfaces of the ACP particles. The events that occur in the immediate post-transition period suggest the hydrolysis of this OCP-like material to an apatitic phase.

Apatites↗

PubMedDate not supplied

A modified technique for tail cuff pressure measurement in unrestrained conscious rats.

In physiological experiments, it is essential to measure arterial pressure (AP) and heart rate (HR) in animals. Tail cuff pressure (TCP) measurement using photoelectric volume oscillometry has been commonly used. We designed a new technique for continuous measurement of AP and HR in conscious, unrestrained rats. This is based on the observation that fixation of the rat's tail with tape keeps the animal in position without struggling. The animal is free to move its body. To test the accuracy of this new technique, Sprague-Dawley rats underwent four AP and HR measurement techniques. These included a new unrestrained method (UR), which was compared to the following three methods: traditional restrained TCP method with restrainer, direct monitoring of AP and HR with femoral artery catheterization and a combination of photoelectric volume oscillometry (with body heating to 37 degrees C) and femoral arterial recording. The results show that the modified UR measurement provides accurate data on AP and HR. This method obtains a lower value of HR and similar mean AP when compared to direct monitoring from femoral arterial catheterization. Accordingly, the modified unrestrained TCP measurement can be used in conscious rats as a noninvasive method.

Animals↗

PubMed1992

Nosology of spastic tetraplegic cerebral palsy: clinical review of fifty cases.

The aim of this study is to contribute to the definition of tetraplegic cerebral palsy (TCP) and to verify the classification criteria currently used by reviewing the clinical and neurological aspects of 50 children having non-progressive encephalopathy with neurological involvement of 4 limbs (symmetric 4-limb type, side-asymmetric type, upper-limb dominated type with or without dystonic traits). All severe diplegic patients, i.e. less upper than lower limb involvement and patients with dystonic hyperkinetic syndrome without spastic features were excluded. The data were supplied by the hospital records, evolution of motor performance and the presence or absence of epilepsy, visual problems, language disorders, intellectual impairment. All the children underwent: neurological examination, functional assessment, cognitive evaluation. Severe motor impairment was found in 80% of the patients, whose clinical characteristics led to a diagnosis of severe TCP or "true TCP" according to Hagberg, whereas 20% of them showed mild to moderate impairment with a more favorable prognosis. This group of patients complied with the classification of Michaelis who defined the quadrispastic CP types more broadly and delineated five subgroups also including cases with milder involvement (side-dominated, three-limb dominated tetraparesis). The intellectual assessment showed that, in the severely affected patients, only a small percentage had severe intellectual impairment (IQ less than 50, 37.5%), which contrasts with published data on this pathology, while the majority of the subjects showed moderate (25%) or mild intellectual impairment (32.5%) or normal cognitive function (5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1983

ESR spectra of VO2+ ions adsorbed on calcium phosphates.

The ESR spectra of oxovanadium(IV) ions, (VO2+), adsorbed on hydroxyapatite(OHAp), fluorhydroxyapatite(FHAp), Mg-containing tricalcium phosphate(Mg-TCP), .octacalcium phosphate (OCP), dicalcium phosphate dihydrate (DCPD), and amorphous calcium phosphate(ACP) were measured at room temperature. The ESR parameters of VO2+ adsorbed on these compounds were slightly different from one another and accordingly, the ESR technique by use of VO2+ was useful for an analysis of the calcium phosphates precipitated from supersaturated solutions. The ESR parameters of VO2+ adsorbed on ACP and Mg-TCP were found to be very similar to each other, suggesting that ACP and TCP resemble each other in the structure of their crystal surfaces.

Adsorption↗

PubMed1990

Formation of carbonate-apatite crystals after implantation of calcium phosphate ceramics.

The aims of this study were (1) to determine at the crystal level, the nonspecific biological fate of different types of calcium phosphate (Ca-P) ceramics after implantation in various sites (osseous and nonosseous) in animals and (2) to investigate the crystallographic association of newly formed apatitic crystals with the Ca-P ceramics. Noncommercial Ca-P ceramics identified by X-ray diffraction as calcium hydroxylapatite (HA), beta-tricalcium phosphate (beta-TCP), and biphasic calcium phosphates (BCP) (consisting of beta-TCP/HA = 40/60) were implanted under the skin in connective tissue, in femoral lamellar cortical bone, articular spine bone, and cortical mandibular and mastoidal bones of animals (mice, rabbits, beagle dogs) for 3 weeks to 11 months. In humans, HA or beta-TCP granules were used to fill periodontal pockets, and biopsies of the implanted materials were recovered after 2 and 12 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1999

The experimental study on mixed culture of osteoblasts and tricalcium phosphate ceramics in vitro.

To study the effects of tricalcium phosphate (TCP) ceramics on osteoblasts, the rat osteoblasts were cultured with the TCP ceramics in vitro. Scanning electron microscopy and the colorimetric methyl-thiazol-tetrazolium assay showed that the osteoblasts could adhere well to the surface of the ceramics and the culture dish, and the proliferation of the cells was not inhibited. The results demonstrated that TCP ceramics possessed an excellent cytocompatibility with the osteoblasts, and had some promoting effects on proliferation of osteoblasts.

Animals↗

PubMed1998

[Integration properties of bone substitute materials. Experimental studies on animals].

In order to avoid the potential risks of disease transmission in allograft surgery, numerous substitute materials have been described. As the biological response to implant materials is different, we undertook the following study to assess type and amount of bone ingrowth in CaP-ceramics. 105 cylindrical bone defects with a diameter of 5.4 mm were created surgically in the femoral condyles of 53 skeletal mature NZW rabbits. The defects were filled with crushed coralline hydroxyapatite (HA) implants (n = 21), synthetically produced hydroxyapatite (n = 21) and surface-modified alpha-Tricalciumphosphate (TCP) grains (n = 21). 21 defects were left empty and other drill holes were filled with rabbit cancellous bone cylinders (n = 21) after 3 months of cryopreservation at -78 degrees C without sterilization. Following observation periods of 2, 4, 6, 8, 12, 26 and 52 weeks the femoral condyles were harvested for histological evaluation and quantitative analysis of bone ingrowth. Woven bone formation at implant periphery can be observed in all substances as early as 2 weeks postoperatively. At 4-week-intervals cryopreserved allografts show new bone apposition on surfaces of necrotic trabeculae and graft-host junctions by a predominantly osteoblastic reaction at the periphery of all cylinders, while in HA- and TCP-grains early bone formation in the center of drill holes is detectable as well. There is a direct contact between HA-/TCP-particles and newly formed bone without fibrous tissue formation at the implant surfaces. Central new bone formation in rabbit allografts can be observed after 6 to 8 weeks together with a secondary osteoclastic resorption of necrotic transplant trabeculae. The result of this remodeling process is a complete degradation of transplant cylinders with reorganization of vital trabeculae oriented in a mature pattern after 12 to 26 weeks. In contrast the HA- and TCP-implants did not show any signs of resorption.

Animals↗

PubMed2002

A capillary-based amperometric flow immunoassay for 2,4,6-trichlorophenol.

This paper describes the development of two different capillary-based heterogeneous competitive flow immunoassay formats (capillary flow injection immunoassay (CFIIA) and capillary sequential injection immunoassay (CSIIA)) for the determination of 2,4,6-trichlorophenol (2,4,6-TCP). The assays are based on the competition between the analyte and an analyte derivative labelled with the enzyme beta-galactosidase, for an anti-TCP antibody, followed by the injection of the mixture at equilibrium into a flow stream, where separation between the fractions bound and unbound to the antibody is performed in a glass capillary containing immobilised protein A. The antibody-tracer fraction retained inside the protein A capillary was measured by injection of 4-aminophenyl- beta- D-galactoside (4-APG), followed by amperometric detection of the enzymatically generated 4-aminophenol (4-AP), leading to a negative correlation between the signal and the analyte concentration. The two immunoassay formats were compared in terms of sensitivity and speed, giving IC(50) values of 1.41+/-0.03 and 1.64+/-0.07 micro g L(-1), detection limits of 0.2 and 0.4 micro g L(-1), and sample throughputs of 6 and 4 h(-1) for the CFIIA and CSIIA system, respectively. The influence of different interfering chlorophenolic compounds in the assay was minor, with only one exception (i.e. 2,4-dichlorophenol). In addition, different water matrices were tested (surface, tap, and rain water), showing that the matrix influence was negligible, except for rainwater, which resulted in a 30% increase in sensitivity. As a conclusion, the assay is suitable for the fast screening of TCP present at low concentration levels in water samples.

Antibodies, Monoclonal↗