[Study on objective structured clinical assessment].
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Holistic Nursing↗
Biomedical subjects
X Q Li
Publications and source records attributed to X Q Li.
p53 overexpression in Ewing's sarcoma/primitive neuroectodermal tumour is an uncommon event.
Aim-To determine the presence of p53 overexpression in Ewing's sarcoma/primitive neuroectodermal tumours (ETs) and to assess whether p53 accumulation has any prognostic value.Methods-From a prospectively compiled database of 76 patients with ETs, suitable tumour tissue was available for 38. The monoclonal antibody pAb1801 was used to detect p53 nuclear protein overexpression. Results-Nuclear staining was detected in the tumours of three (8%) of the 38 patients. Where tumours stained positively, over 10% of the tumour nuclei were postively stained. All three patients whose tumours overexpressed p53 died and in a relatively short time compared with the patients who did not overexpress p53 (mean 3.7 months compared with a mean of 38.7 months in the p53 negative group).Conclusion-Overexpression of p53 in ETs is an uncommon event. Overexpression of p53 has repeatedly been shown to correlate closely with p53 point missense mutations and therefore this oncogenic event appears not to be of primary pathogenic importance in ETs. There is a tentative indication that those uncommon ETs in which p53 overexpression can be detected may be-have more aggressively.
Journal Article↗
AMPA antagonist LY293558 does not affect the severity of hypoxic-ischemic injury in newborn pigs.
BACKGROUND AND PURPOSE: LY293558 is a systemically active alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) excitatory amino acid antagonist. AMPA antagonists have shown promise in several adult hypoxic-ischemic brain injury models, and we wanted to see if this work could be extended to a newborn animal. METHODS: Seventy-six (beta error < .10) 0- to 3-day-old piglets under 1.5% isoflurane anesthesia underwent placement of carotid snares and arterial and venous catheters. While paralyzed with succinylcholine under 0.5% isoflurane, 50% nitrous oxide, piglets were randomly assigned to receive either 5 mg/kg or 15 mg/kg of LY293558 or saline at time--10 minutes and again 10 hours later. At time 0, both carotid arteries were clamped, and blood was withdrawn to reduce the blood pressure to two thirds of normal. At time 15 minutes, inspired oxygen was reduced to 6%. At time 30 minutes, the carotid snares were released, the withdrawn blood was reinfused, and the oxygen was switched to 100%. On the third day after the hypoxic-ischemic injury, the animals were killed by perfusion of the brain with 10% formalin. Brain pathology was scored by a blinded observer. RESULTS: There were no significant differences between the drug-treated and control groups. CONCLUSIONS: The systemically active AMPA antagonist LY293558, when given at a dose of 5 mg/kg or 15 mg/kg before injury and 10 hours later, does not affect the severity of hypoxic-ischemic brain injury in newborn piglets. Neither AMPA receptor activity nor NMDA receptor activity are important in brain injury in this model.
Animals↗
Insulin-like growth factor I regulation of Swarm rat chondrosarcoma chondrocytes in culture.
Insulin-like growth factor I (IGF-I) is anabolic for chondrocytes and is thought to be important in regulating such normal cartilaginous tissues as the epiphyseal growth plate. In the present studies, we have investigated the role of IGF-I in the regulation of neoplastic cartilage. Chondrocytes cultured from a transplantable rat chondrosarcoma were analyzed for responsiveness to IGF-I with respect to DNA and glycosaminoglycan synthesis as determined by labeling with radioactive thymidine and sulfate, respectively. Stimulation of [3H]thymidine and [35S]sulfate incorporation by IGF-I was two to four times that in serum-free controls, with half-maximal stimulation at 1 x 10(-9) M. The efficacy of IGF-I was approximately one-half of that of serum in stimulating [3H]thymidine incorporation and was comparable to that of serum for [35S]sulfate incorporation. When Swarm rat chondrosarcoma chondrocytes were cultured in the presence of IGF-I and exposed to graded concentrations of anti-IGF-I antibody, [3H]thymidine incorporation and [35S]sulfate incorporation were attenuated in a dose-dependent fashion to 29 and 25% of antibody-free controls, respectively. Nonspecific antibody not raised against IGF-I was not inhibitory. These observations suggest that the majority of IGF-I action on these cells is susceptible to immunoinhibition. To estimate the contribution of IGF-I to the regulation of these cells by serum, Swarm rat chondrosarcoma chondrocytes were cultured with graded concentrations of either calf serum or fetal calf serum in the presence of anti-IGF-I antibody, nonspecific antibody, or no other additives. Specific antibody attenuated the effect of calf serum on both [3H]thymidine and [35S]sulfate incorporation with overall inhibition of 52% (P < 0.01) and 48% (P < 0.001), respectively. Nonspecific antibody super-imposed small, variably stimulatory or inhibitory effects on those of calf serum. When chondrosarcoma chondrocytes were incubated with fetal calf serum, anti-IGF-I antibody exerted a minimal inhibitory effect, reducing both [3H]thymidine and [35S]sulfate incorporation by less than 25%. The immunoinhibition of both pre- and postnatal serum could be overcome in a dose-dependent fashion by increasing serum concentrations. These results suggest that the factors influencing Swarm rat chondrosarcoma chondrocytes may be developmentally regulated and that the contribution of IGF-I to the action of serum increases between fetal and post-natal life. These data support the hypothesis that chondrosarcoma is a somatomedin-responsive neoplasm and suggest that this tumor may be susceptible to interventions directed toward mechanisms that block insulin-like growth factor action.
Animals↗
Increased intestinal vitamin D receptor in genetic hypercalciuric rats. A cause of intestinal calcium hyperabsorption.
In humans, familial or idiopathic hypercalciuria (IH) is a common cause of hypercalciuria and predisposes to calcium oxalate nephrolithiasis. Intestinal calcium hyperabsorption is a constant feature of IH and may be due to either a vitamin D-independent process in the intestine, a primary overproduction of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], or a defect in renal tubular calcium reabsorption. Selective breeding of spontaneously hypercalciuric male and female Sprague-Dawley rats resulted in offspring with hypercalciuria, increased intestinal calcium absorption, and normal serum 1,25(OH)2D3 levels. The role of the vitamin D receptor (VDR) in the regulation of intestinal calcium absorption was explored in 10th generation male genetic IH rats and normocalciuric controls. Urine calcium excretion was greater in IH rats than controls (2.9 +/- 0.3 vs. 0.7 +/- 0.2 mg/24 h, P < 0.001). IH rat intestine contained twice the abundance of VDR compared with normocalciuric controls (536 +/- 73 vs. 243 +/- 42 nmol/mg protein, P < 0.001), with no difference in the affinity of the receptor for its ligand. Comparable migration of IH and normal intestinal VDR on Western blots and of intestinal VDR mRNA by Northern analysis suggests that the VDR in IH rat intestine is not due to large deletion or addition mutations of the wild-type VDR. IH rat intestine contained greater concentrations of vitamin D-dependent calbindin 9-kD protein. The present studies strongly suggest that increased intestinal VDR number and normal levels of circulating 1,25(OH)2D3 result in increased functional VDR-1,25(OH)2D3 complexes, which exert biological actions in enterocytes to increase intestinal calcium transport. Intestinal calcium hyperabsorption in the IH rat may be the first example of a genetic disorder resulting from a pathologic increase in VDR.
Animals↗
[Pathophysiological basis of 3 subtypes in ganfeng neidong syndrome].
The multiple parameters of 3 Subtypes: Ganyang Huafeng Syndrome (GYHFS), Xuexu Shengfeng Syndrome and Yinxu Fengdong Syndrome of Ganfeng Neidong Syndrome were determined for the 1st time. It was found that there were several characteristics in GYHFS. (1) Disturbance of the cerebral blood flow and the damage of brain tissue was manifested by the abnormality of the bulbar conjunctival microcirculation, carotid Doppler ultrasonic determination and brainstem auditory and visual pathway, high blood viscosity, dysmnesia, free radical and lipid peroxidation injury and the changes of Zn, Cu, K and Mg after brain damage. (2) Stress status were expressed by the high plasma levels of cortisol, norepinephrine and epinephrine, decreased serum triiodothyronine level and hyperfunction of sympathetic nerve. (3) The marked changes of the regulating substance of the vessel smooth muscle function including the increased plasma levels of TXB2, TXB2/6-k-PGF1 alpha, and calmodulin, as well as decreased SP, ANP, CGRP. Other 2 subtypes had about the same changes of these parameters, but of milder disorders.
6-Ketoprostaglandin F1 alpha↗
Factors influencing Agrobacterium-mediated transient expression of gusA in rice.
Transient expression of GUS in rice (Oryza sativa L.) mediated by Agrobacterium tumefaciens was characterized using binary vectors containing gusA genes that express minimal (pKIWI105 and pCNL1) or no (p35S-GUS-INT and pCNL56) GUS activity in bacteria. Four-day old seedlings obtained from seeds or immature embryos of rice were cut into shoot, root, and seed remnants and inoculated with various strains of A. tumefaciens. Transient GUS expression events were quantitated histochemically by determining the frequency of explants exhibiting blue spots indicative of GUS at four to six days after cocultivation with A. tumefaciens. A. tumefaciens strains that did not contain the gusA gene (At643) or a Ti-plasmid (At563 and At657) did not elicit any blue staining characteristic of GUS activity. Several parameters were important in obtaining efficient transient expression of GUS in rice mediated by A. tumefaciens. The growth regulator 2,4-D inhibited GUS expression if present during the seed germination period, but the presence of 6 mg/l 2,4-D during cocultivation of the explants with A. tumefaciens slightly enhanced GUS expression efficiency. All 21 rice cultivars tested expressed GUS after co-cultivation with A. tumefaciens. The GUS expression frequency was highest amongst the indica cultivars. The frequencies of GUS expression in japonica cultivars and in Oryza glaberrima cultivars (grown primarily in Africa) were generally one-half to one-third the level found for indica varieties. Leaf explants were more susceptible to A. tumefaciens-facilitated GUS expression than were roots or seed remnants. The vir genes of an agropine-type Ti-plasmid of A. tumefaciens were most effective in directing transient GUS expression in rice, whereas those of a nopaline-type and an octopine-type plasmid were less effective. We have also found that the frequency of transient expression of GUS was higher with pBIN19 as the precursor cloning vector than with pEND4K as the precursor cloning vector. Reasons for differences in effectiveness of these binary vectors are discussed. Using the conditions described here, A. tumefaciens-mediated frequencies of transient GUS expression in four-day old shoots of several rice cultivars were routinely in excess of 50%.
2,4-Dichlorophenoxyacetic Acid↗
Multiple copies of virG enhance the transient transformation of celery, carrot and rice tissues by Agrobacterium tumefaciens.
In an effort to improve the T-DNA-mediated transformation frequency of economically important crops, we investigated the possible enhancement effect of multiple copies of virG genes contained in Agrobacterium tumefaciens strains upon the transient transformation of celery, carrot and rice tissues. Four days after A. tumefaciens infection, we performed histochemical beta-glucuronidase (GUS) assays to determine the frequency of transient transformation of calli from celery and carrot, and explants from rice and celery. Additional copies of octopine- and agropine-type virG genes in A. tumefaciens strains containing an agropine-type Ti-plasmid enhanced the frequency of transient transformation of celery and rice. This enhancement ranged from 25% to five-fold, depending upon the source of the virG gene and the plant tissues inoculated. For both rice and celery, we observed a greater enhancement of transformation using A. tumefaciens strains containing additional copies of an octopine-type virG gene than with strains harboring additional copies of an agropine-type virG gene. Multiple copies of virG genes contained in A. tumefaciens strains harboring a nopaline-type Ti-plasmid had a smaller enhancing effect upon the transformation of celery tissues, and no enhancing effect upon the transformation of rice. In contrast, we obtained a three-fold increase in the transient transformation frequency of carrot calli using an A. tumefaciens strain harboring a nopaline-type Ti-plasmid and additional copies of an octopine-type virG gene. Our results show that multiple copies of virG in A. tumefaciens can greatly enhance the transient transformation frequency of celery, carrot and rice tissues, and that this enhancement is influenced by both the type of Ti-plasmid harbored by A. tumefaciens and by the infected plant species.
Agrobacterium tumefaciens↗
Cleavage specificity of chloroplast and nuclear tRNA 3'-processing nucleases.
tRNAs in eukaryotic nuclei and organelles are synthesized as precursors lacking the 3'-terminal CCA sequence and possessing 5' (leader) and 3' (trailer) extensions. Nucleolytic cleavage of the 3' trailer and addition of CCA are therefore required for formation of functional tRNA 3' termini. Many chloroplast tRNA genes encode a C at position 74 which is not removed during processing but which can be incorporated as the first base of the CCAOH terminus. Sequences downstream of nucleotide 74, however, are always removed. Synthetic yeast pre-tRNA(Phe) substrates containing the complete CCA74-76 sequence were processed with crude or partially purified chloroplast enzyme fractions. The 3'-extended substrates (tRNA-CCA-trailer) were cleaved exclusively between nucleotides 74 and 75 to give tRNA-COH, whereas a 3'-mature transcript (tRNA-CCAOH) was not cleaved at all. A 5'-, 3'-extended chloroplast tRNA-CAG-trailer was also processed entirely to tRNA-COH. Furthermore, a 5'-mature, 3'-extended yeast pre-tRNA(Phe) derivative, tRNA-ACA-trailer, in which C74 was replaced by A, was cleaved precisely after A74. In contrast, we found that a partially purified enzyme fraction (a nuclear/cytoplasmic activity) from wheat embryo cleaved the 3'-extended yeast tRNA(Phe) precursors between nucleotides 73 and 74 to give tRNA(OH). This specificity is consistent with that of all previously characterized nuclear enzyme preparations. We conclude that (i) chloroplast tRNA 3'-processing endonuclease cleaves after nucleotide 74 regardless of the nature of the surrounding sequences; (ii) this specificity differs from that of the plant nuclear/cytoplasmic processing nuclease, which cleaves after base 73; and (iii) since 3'-mature tRNA is not a substrate for either activity, these 3' nucleases must require substrates possessing a 3'-terminal extension that extends past nucleotide 76. This substrate specificity may prevent mature tRNA from counterproductive cleavage by the 3' processing system.
Base Sequence↗
[Experimental study and evaluation of pulpotomy with hydroxyapatite].
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Animals↗
[Duodeno-biliary reflux during T-tube drainage: a clinical study].
The relationship between duodeno-biliary reflux and bile bacterial contamination was studied in 28 consecutive cases of T-tube drainage after cholecystectomy and choledochotomy. Patients were randomly divided into two groups of 14 each. Group I treated with positive pressure drainage (PPD), with the pressure in T-tube 0.3-0.5 kPa higher than that created by sphincter resistance. Group II treated with traditional negative pressure drainage (NPD). It was found that the amount of duodenal reflux in group II was obviously larger than that in group I. We conclude that the traditional T-tube drainage incurs inevitably contamination of bacteria to bile by way of duodenal reflux. It is the consequence of bile flow dynamic disorder. PPD raises the bypass outflow resistance against the duodenal reflux and is thus superior to NPD.
Bile↗
Positive Darwinian evolution in human influenza A viruses.
We earlier suggested that type A human influenza virus genes undergo positive Darwinian selection through immune surveillance. This requires more favorable amino acid replacements fixed in antigenic sites among the surviving lineages than among the extinct lineages. We now show that viral hemagglutinins fix proportionately more amino acid replacements in antigenic sites in the trunk of the evolutionary tree (survivors) than in the branches (nonsurvivors), demonstrating that type A human influenza virus is undergoing positive Darwinian evolution. The hemagglutinin gene is evolving 3 times faster than the nonstructural gene and the average age of the sampled nonsurvivors is only 1.6 years, so that extinction is not only common but rapid.
Amino Acid Sequence↗
Differential patterns of incorporation and remodeling among various types of bone grafts.
The early (3 months) and later (6 months) patterns of incorporation and bone formation have been evaluated histomorphometrically for different types of bone grafts; that is, vascularized and nonvascularized autografts with and without ciclosporin, and vascularized and nonvascularized dog leukocyte antigen (DLA)-mismatched allografts with and without ciclosporin. The vascularized bones were superior to the nonvascularized ones in healing and remodeling their grafted segments. In the autograft bones, ciclosporin did not alter the incorporation process 3 months after transplantation but delayed and increased the remodeling activities in the long run (6 months). Nonvascularized allografts underwent vigorous resorption, and were markedly porotic. Ciclosporin administration significantly reduced resorption and enhanced remodeling in nonvascularized allografts. The remodeling of allografts was similar to that of autografts in the presence of ciclosporin, but stopped soon after the administration of ciclosporin ceased.
Animals↗
[Experimental study on the treatment of hypertension with combined traditional Chinese and Western medicine].
In order to study the connection of diastolic activity of smooth muscles of blood vessels with development of hypertension, plasma cAMP, cGMP, TXB2, 6-K-PGF1 alpha, ANP, SP were determined with radioimmunoassay, of 173 hypertension patients with Liver Yang exuberance (LYE) 91 cases, and Yin deficiency and Yang exuberance (YDYE) 82 cases. In addition, 228 health subjects served as control. The results showed that the levels of cAMP, cGMP and TXB2 in both LYE and YDYE groups were higher than those in the control group, but the levels of ANP, SP and cAMP/cGMP ratio in LYE and YDYE groups were lower than those in the control. As to the level of 6-K-PGF1 alpha, no significant variance was found between these groups. After TCM-WM treatment, the levels of cAMP, cGMP and TXB2 in LYE and YDYE groups got down, as compared with those in the control, adversely the levels of ANP, SP and 6-K-PGF1 alpha in LYE and YDYE groups turned up significantly. However the cAMP/cGMP ratio had no remarkable change between these groups. The linear regression analyses between the diastolic pressure and ANP or SP both proved negative correlation (r = -0.36, P less than 0.05; r = -0.35, P less than 0.05). The findings indicated that the TCM-WM treatment was the most effective among the therapies employed in the study, and that this therapy affected the diastolic activity of smooth muscles by modulating the above factors existing in the nervous and endocrine systems of the patients with hypertension.
6-Ketoprostaglandin F1 alpha↗
The fate of cancellous and cortical bone after transplantation of fresh and frozen tissue-antigen-matched and mismatched osteochondral allografts in dogs.
After implantation, a massive osteochondral allograft cannot be completely protected from the stresses that are produced by weight-bearing, and it is susceptible to collapse during incorporation, revascularization, and substitution. How these processes are affected by disparities between the tissue antigens of the host and the graft remain unclear. To clarify the role of histocompatibility antigen-matching in the incorporation of cancellous and cortical bone, we orthotopically implanted both fresh and cryopreserved dog leukocyte-antigen-matched and mismatched proximal osteochondral radial allografts in beagles. Four groups of beagle dogs were used; they received (1) a dog leukocyte-antigen-mismatched frozen allograft, (2) a dog leukocyte-antigen-mismatched fresh allograft, (3) a dog leukocyte-antigen-matched fresh allograft, or (4) a dog leukocyte-antigen-matched frozen allograft. In twelve dogs, a sham operation was done in the contralateral limb (the first living donor had a sham operation), and in the remaining ten dogs, the proximal part of the contralateral radius was removed and then replaced as an autogenous (control) graft. The animals were given fluorochromes periodically, and they were killed eleven months after the operation. The osseous portion of the grafts was evaluated radiographically, biomechanically, and histomorphometrically. No dog had grossly obvious clinical abnormalities, all host-graft interfaces healed, and no joints dislocated. Radiographic examination of the allografts frequently showed deformation of the radial head and variable peripheral resorption. No significant difference in the modulus of elasticity at the host-graft interface was found among the groups. The repair process of the cortical bone was similar for all grafted segments. New periosteal and endosteal bone formed, and the cortical bone became porotic as vessels penetrated it. The uptake of fluorochrome was the most active in the autogenous grafts and the least active in the fresh antigen-mismatched grafts. The volume of cancellous bone was significantly greater and the trabeculae were thicker in all allografts compared with the bones on which a sham operation had been done and compared with the autogenous grafts. The volume of intertrabecular fibrous connective tissue was directly proportional to the immunogenicity of the allografts, and the percentage of the surface on which bone was forming tended to be inversely proportional to the immunogenicity of the allografts. The grafts were revascularized by the ingrowth of vessels into the intertrabecular spaces; necrotic trabeculae were not penetrated by vessels. This pattern was particularly pronounced in the antigen-mismatched grafts, regardless of whether they were fresh or frozen.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
Purification of a reconstitutively active K+/H+ antiporter from rat liver mitochondria.
We describe purification of three different states of the 82-kDa K+/H+ antiporter from rat liver mitochondria. The denatured 82-kDa protein, identified by its selective labeling with [14C]dicyclohexylcarbodiimide (DCCD), was purified by preparative two-dimensional gel electrophoresis. This purified product was used to raise and immunopurify monospecific polyclonal antibodies. Western blot analysis showed that the [14C] DCCD-labeled 82-kDa protein is not a DCCD-crosslinked product. The native, [14C]DCCD-labeled, 82-kDa protein was purified by (NH4)2SO4 fractionation and column chromatography, using 14C labeling and gel electrophoresis to track the protein. The native, non-DCCD-labeled 82-kDa protein was purified by similar procedures, using immunopurified antibodies to track the protein. DCCD binding had no effect on chromatographic behavior of the antiporter protein. This protocol resulted in purification of the 82-kDa protein to apparent homogeneity. The purified, native 82-kDa protein was reconstituted into proteoliposomes and assayed for K+ transport with the new fluorescent probe, PBFI. K+ transport was electroneutral and was inhibited by DCCD, Mg2+, and timolol. The turnover number for K+ transport was about 1000 s-1, very similar to the value previously estimated in intact mitochondria.
Animals↗
Simultaneous measurement of bone formation and resorption in vivo.
Bone resorption and formation in terms of milligram of calcium deposited into and released from whole humerus of 15-23 weeks old male rats were assessed, via linear least-squares regression analysis of change in calcium content and 3H-tetracycline kinetics of the bone. The rate of resorption was 0.376 mg calcium per day, while formation was 0.758 mg calcium per day. The data indicate that the computation results in a simultaneous and explicit measurement of bone resorption and formation at the organ level.
Animals↗
Decreasing rates of bone resorption in growing rats in vivo: comparison of different types of bones.
This study quantifies rates of bone resorption by measuring the kinetic loss of 3H-tetracycline in vivo from the five different types of whole bones in four ages of normal male rats: appendicular bone (femur), cephalic bone (calvarium), axial bones (sixth lumbar vertebrae and sternum), and pelvis. The skeletons of newborn (0-2 weeks), weanling (4-7 weeks), adolescence (10-14 weeks), and mature (15-23 weeks) of Sprague Dawley rats were multiply labeled with 3H-tetracycline. The radioactivity in whole calvaria, the 6th lumbar vertebra, sternum, pelvis and femur was quantified to calculate the time course of tetracycline loss. The isotopic half lives (t1/2) were different for each age group and each bone, but the rates of resorption were usually the highest in the newborn rats. In the youngest animals, the t1/2 for the femur, vertebrae, and sternum was 1.5 week, for the pelvis it was 2.0 week, and for the calvarium it was 2.5 week. In the oldest age group, t1/2 for the femur was 28 week, for the calvarium was 19 week, for the sternum and pelvis was 16.5 week, and for the vertebrae was 13 week. For cephalic bones and femur, the greatest decrement in the rate of resorption occurred in the first 7 weeks of life (-52% and -72%, respectively). The axial bones and pelvis maintained a uniformly high resorptive rate until 7 weeks of age, which waned sharply at adolescence (-70% to -78%). At maturity the resorptive rate of these bones was less than 16% of the rate in the newborn.(ABSTRACT TRUNCATED AT 250 WORDS)
Aging↗