Irreversibility temperatures of Nb3Sn and Nb-Ti.
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Journal Article↗
Biomedical subjects
Y Xu
Publications and source records attributed to Y Xu.
Irreversibility temperatures in superconducting oxides: The flux-line-lattice melting, the glass-liquid transition, or the depinning temperatures.
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Journal Article↗
In vivo induction of bone by recombinant human transforming growth factor beta 1.
A single application of recombinant human transforming growth factor beta 1 (rhTGF-beta 1) adjacent to cartilage was found to induce bone formation in rabbit ear full-thickness skin wounds. At doses that optimally promote soft tissue healing, 25-100 ng rhTGF-beta 1 per wound caused osseous tissue formation starting 21 days after wounding to reach a peak incidence and area of bone formation at day 42. Bone formation was followed by active remodeling, resulting in lower incidence and area of bone formation at days 56 and 70. The early phase of bone formation was located overlying the cartilage and involved perichondrial cells that appeared to differentiate directly into osteoblasts forming bone matrix without a cartilage precursor. Cartilage was replaced with bone at later time points. rhTGF-beta 1 was able to increase the ratio of osteoblasts to osteoclasts lining the trabecular surface of bone and thus increase the net amount of bone formation. The present studies suggest a potential therapeutic role for rhTGF-beta 1 in hard tissue repair.
Animals↗
Rapid publication. TGF-beta 1 induces bone closure of skull defects.
Transforming growth factor beta 1 (TGF-beta 1) is a multifunctional regulatory protein. It is capable of inducing site-specific healing responses by increasing collagen synthesis and deposition as well as remodeling at sites of soft tissue repair. Large bony defects in the skull heal by fibrous connective tissue and never form bone unless osteoinductive bony fragments or powders are placed in the defect. We have found, however, that the single application of human recombinant TGF-beta 1 in a simple 3% methylcellulose gel to skull defects induced a dose-dependent increase in intramembranous bone formation. Complete bony bridging of defects occurred within 28 days after treatment with 2 micrograms TGF-beta 1. Sites treated with vehicle alone did not heal with bone formation but rather contained dense fibrous connective tissue between the defect margins.
Animals↗
Nonleptonic weak decay of Lambda 5He and Lambda 12C.
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Journal Article↗
The prevalence of chromosome diseases in the general population of Sichuan, China.
Chromosome abnormalities with recognizable clinical manifestations including mental retardation, primary infertility or primary amenorrhea of unknown etiology, abnormal sex differentiation and abnormal sex development were surveyed in the general population of Sichuan. The results showed that the prevalence of chromosome diseases in Sichuan was 31.5 per 100,000 of the general population with almost equal frequencies for autosomal chromosome and sex chromosome diseases. The most frequent autosomal chromosome disease was Down syndrome. The prevalence was 14.2 per 100,000 for the total population, and there should therefore be 154,000 cases of Down syndrome in the whole of China with its population of 1,100 million people. The most frequent sex chromosome diseases were Turner syndrome and Klinefelter syndrome. The prevalences were 14.3 and 14.1 per 100,000 for females and males, respectively. The majority of autosomal chromosome diseases clustered in the younger age groups, while the highest detection rate of sex chromosome diseases was found in the age group of 25-35, and thereafter it decreased with age. The age distribution of the cases indicates that both autosomal and sex chromosome diseases reduce the lifespan of patients.
Adolescent↗
Tolerance of low cerebral intracellular pH in rats during hyperbaric hypercapnia.
BACKGROUND AND PURPOSE: Brain acidosis from cerebral ischemia is characterized by average intracellular pH levels of approximately 5.8-6.2, which appear in turn to worsen cellular injury. We report that the brain is not injured when hypercapnia is used to reduce intracellular pH to about 6.2 during adequate oxygenation. A hyperbaric chamber is needed to achieve intracellular pH values so low because inspired CO2 tensions must be increased to approximately 1 atm. SUMMARY OF REPORT: Using in vivo phosphorus-31 and proton nuclear magnetic resonance spectroscopy, we measured brain intracellular pH and lactate concentration of rats inside a nonmagnetic polycarbonate chamber at a barometric pressure of 1,500 mm Hg. Intubated rats were ventilated with a 50% O2/50% CO2 gas mixture for specific times. All six rats ventilated for 15 minutes with CO2 tensions of approximately 750 mm Hg woke up without neurological impairment, despite a decrease in intracellular pH to about 6.2. Higher CO2 tensions and longer exposures resulted in cardiovascular collapse and sudden death, followed by the postmortem appearance of brain lactate. CONCLUSIONS: Brain intracellular pH values near 6.2 can be induced briefly in vivo in ventilated rats without injury under hyperbaric hypercapnic conditions. If attempts are made to lower brain pH in vivo even further by increasing PCO2 beyond 750 mm Hg, mean arterial blood pressure and cerebral blood flow decrease to values incompatible with life.
Animals↗
TGF-beta 1 accelerates wound healing: reversal of steroid-impaired healing in rats and rabbits.
TGF-beta modulates events of normal wound healing through multiple pathways that influence cell infiltration, proliferation, angiogenesis, extracellular matrix synthesis and remodeling. The effects of topically applied TGF-beta 1 on wound healing in two models of healing were evaluated when the healing response was impaired by the administration of methylprednisolone to rats or rabbits. TGF-beta 1 increased the healing of linear incision wounds on rats, as measured by breaking strength, to that of normal rats. Full thickness open wounds were also created on the inner ears of rabbits to simulate a non-contracting wound with limited blood supply. Healing was further impaired by the administration of methylprednisolone. The single application of TGF-beta 1 improved the healing of open wounds. TGF-beta 1 stimulated increased granulation tissue formation, as well as reepithelialization. The amount of granulation tissue and epithelialization were similar to wounds from normal-healing control rabbits. The delayed healing caused by methylprednisolone permitted the evaluation of multiple applications of TGF-beta 1 to wounds. Two applications of TGF-beta 1 spaced 7 days apart further improved the healing response when compared to a single application. Thus, single or multiple topical applications of TGF-beta 1 reversed impaired healing conditions secondary to methylprednisolone when used on incisional or open wounds. These observations support the hypothesis that growth factors, such as TGF-beta 1, may be useful as accelerators of wound repair in patients with impaired healing conditions.
Animals↗
Depth of phonological recoding in short-term memory.
In testing the hypothesis that surface phonetic form is included in short-term memory (STM) representation, the tone sandhi phenomenon in Mandarin Chinese was exploited, and, as a prerequisite, the hypothesis that tonal similarity affects STM of verbal material in a tone language was also tested. In Experiment 1, subjects recalled visually presented sequences of seven monosyllabic Chinese morphemes having either the same tone or different tones. More errors were made on the monotonal sequences than on the multitonal sequences, confirming the effect of tonal similarity on STM. In Experiment 2, subjects recalled visually presented sequences of disyllabic nonsense words. The sequences were designed in such a way that half of them were subject to the tone sandhi rule in Mandarin Chinese, whereas the other half were not. The consequence of applying the tone sandhi rule, as designed, was to make all the first characters in the sequences identical in pronunciation, thus creating potential phonological confusion. More errors, indeed, occurred on the sequences subject to the tone sandhi rule than on those not subject to it, indicating the existence of a surface phonetic representation in STM. The findings in this study provide further insight into the phonological mechanism of STM. Different accounts for this mechanism are also discussed in the light of the new findings.
Adult↗
[A novel Chinese beta-thalassemia mutation--4bp deletion (AAAC) downstream from the cap site].
During the molecular study of the Chinese beta thalassemia, we encountered a mutation that could not be detected by any of the oligonucleotide probes specific for the known Chinese beta thalassemia mutations. Molecular cloning and DNA sequencing analysis by both DNA chain termination and PCR direct sequencing methods revealed a previously undescribed mutation--deletion of 4bp (-AAAC) at the positions of nucleotide 40 to 43 from the cap site of the beta globin gene. With this new mutation, an additional Dde I recognition site is created and it could be directly detected by analysis of the abnormal restriction fragment. Unlike the other beta thalassemia mutations, this newly described mutant is the first mutation within the 5' untranslated region of beta globin gene as well as any other genes. This unique example will elicit valuable insight in the relationship between the structure and function of the 5' untranslated sequences.
Base Sequence↗
Plasma shock wave lithotripsy of gallstones in vitro. Animal experiments and clinical application.
It is sometimes very difficult to extract a huge impacted stone through the T-tube fistulous tract by conventional techniques with choledochoscope. To simplify the procedure, a lithotriptor PSW-G type using plasma shock wave to disintegrate the stone was designed. The efficacy to fragmentate stone was investigated both in vitro and in vivo. Stones can be shattered into pieces less than 3 mm in diameter in about 30 times of spark with lower energy ranging from 1.7-3.4 kV and 1-3 J. Animal experiments were carried out to prove the safety of the lithotriptor. There was neither interference with the cardiovascular and respiratory systems nor obvious damage to the adjacent tissue where plasma shock wave applied to break stones. Six patients with retained calculi impacted both in extra- and intra-hepatic duct were successfully treated by plasma shock wave lithotripsy. It appears very useful in dealing with a huge impacted stone in the biliary tract.
Animals↗
Alkaline phosphatase dissolves calcium pyrophosphate dihydrate crystals.
We have shown that yeast pyrophosphatase dissolves calcium pyrophosphate dihydrate (CPPD) crystals in solutions. In this investigation we demonstrate that alkaline phosphatase (ALP) effectively dissolves CPPD crystals in vitro. CPPD dissolution by ALP had a pH optimum of 7.4, which is the optimum pH for its pyrophosphatase (PPiase) activity. The CPPD dissolution and PPiase activity by ALP are magnesium dependent, whereas its phosphoester hydrolytic activity is not. Calcium, which inhibited the enzymatic CPPD dissolution and PPiase activity of ALP had no effect on its phosphoester hydrolytic activity. These data indicate that PPiase activity of ALP is responsible for CPPD dissolution and not its phosphoester hydrolytic activity. Matrix molecules such as proteoglycans and chondroitin sulfate had no effect on the enzymatic and nonenzymatic dissolution of CPPD crystals. ALP acted more effectively on CPPD crystals than on soluble pyrophosphate relative to yeast PPiase. Our data suggest that chondrocyte ALP may play an important role in the dissolution of CPPD crystals in cartilage.
Alkaline Phosphatase↗
[Prevention of in vivo formation of NMBz A and the formation of oesophageal tumour by tea in rats].
Five groups of rats (22 per group) were intubated with precursors of N-Nitrosomethylbenzylamine (NMBzA), i.e. methylbenzylamine (1 mmol/kg) and sodium nitrite (0.5 mmol/kg), and five varieties of Chinese tea. One positive control group was intubated with precursors of NM2A without tea and one negative control group with tap water and sodium nitrite. After 12 week's treatment, significantly less lesions and papillomas in esophageal mucosa, examined by naked eye or by microscope, were found in the tea-treated groups than in the non-tea-treated positive control group. The results confirmed the anti-tumour ability of Chinese tea by blocking the in vivo formation of NMBzA in rats.
Animals↗
Intravenous recombinant tissue-type plasminogen activator in acute myocardial infarction.
The efficacy and safety of intravenously administered recombinant tissue-type plasminogen activator (rt-PA, Boehringer Ingelheim Corp.) was investigated in 10 patients with acute myocardial infarction (AMI). rt-PA was given as a 10 mg bolus dose followed by infusions of 50 mg, 20 mg and 20 mg in three successive hours. All patients underwent baseline coronary angiography before thrombolytic therapy. Ninety minutes after the initiation of rt-PA infusion, recanalization of infarct-related coronary arteries as confirmed by angiography was achieved in 7 patients. The largest reduction in circulating fibrinogen was observed 4 to 6 h after the start of rt-PA infusion--14.3%. Moderate hemorrhage at the sites of arterial puncture occurred in 2 cases, probably as a result of heparin anticoagulation. No other side effects occurred. So rt-PA is an effective and safe thrombolytic agent.
Aged↗
Secondary prevention of myocardial reinfarction with low dose aspirin.
A clinical trial of secondary prevention of reinfarction with low dose aspirin is reported. 50 mg aspirin per day was administered in 216 case. 211 cases did not take aspirin or any other antiplatelet agents as a control group. The follow-up periods in the two groups were 19.4 +/- 12.6 mon and 20.7 +/- 13.0 mon, respectively. There were 175 males in the aspirin group and 137 males in the control group. The incidence of reinfarction was reduced by 65% and platelet aggregation was inhibited obviously in the aspirin group as compared to the control group in men, whereas no significant trends were observed in women.
Aged↗
Inhibited neoplastic phenotype by the c-Ha-ras antisense RNA.
A 2.0 kb fragment DNA plasmid which expresses antisense to the upstream first exon of c-Ha-ras oncogene was transfected into Ha-ras transformed cell lines, GCM-3T3 and REF-4.3. The transfection leads to the inhibition of malignant behaviour, shown by decreasing of growth speed, colony forming ability on soft agar, tumorigenicity in nude mice and increasing of differentiation degree. In GCM-3T3 cells the lung metastasis frequency became much less (from 60% to 12.5%) after the transfection and the expression of ras oncogene product, and p21 protein was obviously decreased in the transfected cells. This work has first shown the inhibitory effect of antisense RNA on neoplastic behaviour in China.
Animals↗
[Comparison of phospholipid in crude and fried semen Dolichos Lablab].
A study of the chemical changes of phospholipid in crude and fried semen Dolichos Lablab was carried out by molybdenum blue colorimetry and TLC scanning. The result shows that both the total phospholipid contents and the molar fraction of phosphatidylcholine in the fried samples are decreased as compared with the crude ones.
Chromatography, Thin Layer↗
Biomechanical properties and collagen fiber orientation of TMJ discs in dogs: Part 1. Gross anatomy and collagen fiber orientation of the discs.
The present study investigated the gross anatomy and collagen fiber orientation of TMJ discs in dogs using macroscopic, stereomicroscopic, light microscopic, and scanning electron microscopic techniques. Results showed that (1) the surface of the disc has an undulated configuration (a "fingerprint pattern" under stereomicroscope), which appears to aid in storing synovial fluid and providing lubrication to the joint; (2) the fine fibrils in the middle part are twisted together tightly, presenting a wavy, winding, lamina layer structure anteroposteriorly that works to absorb shock; (3) the mediolateral fibers are composed of loose and less wavy bundles, and they are crossed perpendicularly by anteroposterior fibers in anterior and posterior bands. In fact, a fibrous anulus in the periphery of the disc is composed of the mediolateral fibers of anterior and posterior bands and the anteroposterior fibers of the medial and lateral portions of the middle band, which suggests a stabilizing function.
Animals↗