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Biomedical subjects

L Xia

Publications and source records attributed to L Xia.

At least 127 records · Page 7Linked to original sources
PubMed1993

[Expression of left ventricular ANF-gene in rat with cardiac hypertrophy].

Plasma concentration of ANF and expression of left ventricular ANF-gene in rats with cardiac hypertrophy induced by abdominal aortic partial ligation were analyzed by RIA and Northern blot respectively. Results showed that plasma concentration of ANF and level of left ventricular ANF-mRNA in cardiac hypertrophic rats increased markedly, indicating that the cardiac load may induce transcription and expression of left ventricular ANF-gene. This effect could be potentiated by intracellular calcium modulator taurine and inhibited by vasodilator hydralazine.

Animals↗
PubMed1992

A surge of gonadotropin-releasing hormone accompanies the estradiol-induced gonadotropin surge in the rhesus monkey.

In several species, the ovulatory LH surge is preceded by a surge of GnRH. Although a role for estradiol in the initiation of the LH surge is well established in the primate, several observations in the rhesus monkey have questioned whether such an estradiol-induced neurosecretory event takes place. We report on GnRH measurements in cerebrospinal fluid (CSF) samples obtained from the third ventricle of intact and ovariectomized (OVX) conscious rhesus monkeys during control periods and throughout the estradiol-induced positive feedback phase. In the first experiment, we measured control GnRH concentrations in CSF collected at 15-min intervals uninterruptedly for a period of 1-5 days in tethered OVX monkeys (n = 4) in their cages without steroid priming. As had been demonstrated previously with the same method in restrained animals, CSF from the third ventricle contained detectable amounts of GnRH. Spontaneous GnRH secretion was pulsatile; overall mean pulse interval was 67.4 (+/- 2.2 SE) min for a total of 177 GnRH pulses. During 2 periods (8 and 6 h) when simultaneous blood and CSF samples were obtained, 14 out of 15 GnRH pulses were accompanied by an LH pulse. To evaluate the effects of an estrogen challenge on GnRH secretion, estradiol benzoate (E2B; 330 micrograms) was given to 4 intact (5 experiments) and to 2 OVX monkeys. CSF collection was initiated 8-24 h before E2B injection and continued for 72-84 h thereafter. E2B administration resulted in a surge of LH and of GnRH in all but one experiment. The mean time of onset of the GnRH surge was 22.0 (+/- 4.0) h after E2B, whereas that of the LH surge was 24.7 (+/- 3.4) h. In contrast to LH, which declined after a peak at 35.2 +/- 3.9 h, the increase in GnRH secretion persisted throughout most of the observation period. The magnitude of the GnRH response differed in the 2 groups; in the intact animals, mean peak GnRH concentration increased 8.9-fold but only 3.8-fold in the OVX monkeys. A similar GnRH surge was observed in 1 OVX monkey, receiving an iv infusion of E2, which produced more physiological concentrations of E2. In this animal, an initial suppression of GnRH concentration in the 24-48 h period after E2 (GnRH control, 14.6 +/- 1.9; post-E2, 4.0 +/- 0.5 pg/ml) preceded the initiation of the GnRH surge which occurred at 54 h after E2.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

[Compatibility of Chinese drugs radix Aconiti carmichaeli with rhizoma Pinelliae].

To find out whether the Chinese drug Radix Aconiti Carmichaeli is compatible with another Chinese drug Rhizoma Pinelliae in preparation, the two medicinal herbs were made into different forms of decoctions. Experiments with these decoctions were carried out to observe the action on isolated hearts of toads and the ECG and acute toxicity on mice. The results showed that in terms of toxicity there was no marked increase in the mixed decoction as compared with the other two decoctions prepared from Radix Aconiti Carmichaeli and Rhizoma Pinelliae separately.

Animals↗
PubMed1992

Growth inhibition and differentiation of promyelocytic cells (HL-60) induced by BC-4, an active principle from Boswellia carterii Birdw.

The induction of cell differentiation and growth inhibition of HL-60 cells by Bc-4, an active principle from Boswellia carterii, was studied in vitro and in vivo. The proliferation of HL-60 cells was found to be inhibited by Bc-4 at a concentration of 5-10 micrograms/ml. Under the action of Bc-4, the acid phosphatase and NBT reduction activities in HL-60 cells were increased, and phagocytosis of cells was also induced. All these activities were concentration dependent. The HL-60 cells were induced by Bc-4 to differentiate into more mature cells morphologically. The in vivo growth of HL-60 cells in mouse subrenal capsules (SRC) and in diffusion chambers inoculated into mice was inhibited by Bc-4 at a dose of 50 mg/kg. The morphology of HL-60 cells treated by Bc-4 in diffusion chambers exhibited characteristics of mature granulocytic cells.

Animals↗
PubMed1992

Study of the relationship between the hepatotoxicity and free radical induced by 1,1,2-trichloroethane and 1,1,1-trichloroethane in rat.

The hepatotoxicity and the relationship between the hepatotoxicity and free radical induced by 1,1,2-trichloroethane (1,1,2-TCE) and 1,1,1-trichloroethane (1,1,1-TCE) were studied by whole animals test and the isolated perfused rat liver test. Enzymatic parameters measured during the test included the assay of levels of glutamic pyruvic transaminase (GPT), sorbital dehydrogenase (SDH) and glutamate dehydrogenase (GDH). The observation of the pathologic changes of the liver by the light microscope and the measurement of the relative total free radical concentration in the liver were also made. The results showed that 1,1,2-TCE caused definite pathologic changes of rat liver. It led to much higher values for GPT, SDH and GDH both in serum and perfusate than 1,1,1-TCE did (P < 0.01). The concentration of perfusate K+ caused by 1,1,2-TCE was higher than that by 1,1,1-TCE (P < 0.01). The value of the relative total free radical concentration induced by 1,1,2-TCE was also greater than that by 1,1,1-TCE (P < 0.05). The results suggested that the hepatotoxicity of 1,1,2-TCE was stronger than that of 1,1,1-TCE. The free radical concentration was increased proportionally to the increase of the hepatotoxicity of 1,1,2-TCE and 1,1,1-TCE. It appeared that free radical may play an important role in the mechanism of the hepatic injury induced by 1,1,2-TCE.

Alanine Transaminase↗
PubMed1990

[The effects of needling acupoint, nonpain and pain stimulation on electroencephalogram (EEG) of somatosensory area analysed by computer].

The present study was to observe the change of EEG power spectrum during acupuncturing, nonpain stimulating and pain stimulating; then to comparatively analyse the effects of acupuncturing acupoint on brain function. The work was performed on 30 normal subjects. Nonpain or pain stimulation was applied to a medial finger, and the intensity of stimulation was determined by subject's report. Acupoints were "Neiguan" and "Jianshi". EEGs were recorded on a tape recorder before, during and after each stimulation. Then EEG power spectrum were analysed by SM-2100 computer. The results were as follows: According to the analysis of EEG power spectrum, in most of subjects, alpha (a) band was shifted to higher band during pain stimulating, there was significant change, P less than 0.05. The highness of a spike was significantly increased during acupuncturing acupoints, P less than 0.02. The ratio of delta power spectra to theta (theta) and delta (delta) power spectra showed increased tendency during acupuncturing or nonpain stimulating, but decreased during pain stimulating. It was indicated that nociceptive pain-stimulation resulted in hyposynchrony of EEG: frequency was increased, amplitude was decreased, alpha rhythm was inhibited to a certain extent; acupuncturing acupoints had the effect which could strengthen the stability of EEG rhythmic activities. We know that EEG rhythmic activities show clearly the stability of balance inside organism. So this result suggested that acupuncturing acupoint could play a role in modulating the balance inside organism and enhancing the stability of brain function.

Acupuncture Points↗
PubMed1989

Polymorphism in porcine somatotropin cDNA sequences.

Three new full-length cDNAs coding for porcine somatotropin (PST) have been cloned. The sequence data indicate a high degree of polymorphism in the PST sequence. All six known PST sequences are different.

Animals↗
PubMed1989

Sequencing of porcine growth hormone cDNA.

Sequences for two pGH cDNAs are reported in this paper. The cDNAs were obtained by reverse transcription from porcine pituitary gland mRNA, cloned, and screened. The results are discussed and the two cDNA sequencings are compared with one by Seeburg et al. and another by Vize et al.

Amino Acid Sequence↗
PubMed1989

Protein extraction with reverse micelles.

Liquid-liquid protein extraction with reverse micelles is a new method for protein separation. We studied the effects of pH, ionic concentration, cation type, and protein molecular mass on performance of an AOT/isooctane reverse micelle system in extraction of lysozyme, trypsin, and pepsin. Extraction was found to be very efficient for low-molecular-mass proteins.

Cations↗
PubMed1986

Evolution of the endoplasmic reticulum during spermiogenesis of the rooster: an electron microscopic study.

The endoplasmic reticulum (ER) of rooster's spermatids was analyzed during spermiogenesis, which was subdivided into eight distinct steps on the basis of changes observed with the electron microscope in the nucleus, acrosome-perforatorium system, manchette, and flagellum. In steps 1 and 2, spermatids' ER cisternae presented the following specializations: A loose network of tubular cisternae was distributed throughout the cytoplasm. Six to eight tight networks of anastomosed tubular cisternae parallel to each other were closely stacked to form a discoid body (1.5-2.5 microns in diameter and 0.5-0.8-micron thick) in which spheroidal vesicles (0.4 micron in diameter) were inserted. Close to and connected with this body, called the alveolar body, there was a stack of annulate lamellae. Large, flattened ER cisternae were seen singly or in piles of two or three running parallel to the nuclear surface. A collection of tubular ER cisternae faced plaques of thickened plasma membranes. These elements of the ER system appear continuous with each other. During steps 3-5 of spermiogenesis, no modification of the alveolar body-annulate lamellae complex was noted; the large flattened ER cisternae disappeared, however, and the broad network of tubular cisternae developed markedly. During steps 6 and 7, the latter network of tubular cisternae fragmented into vesicles that swelled to give a vacuolated appearance to the cytoplasm. The alveolar body-annulate lamellae complex remained visible until late step 7, when it disintegrated just before spermiation. Thus the system of ER cisternae underwent marked structural modifications during spermiogenesis.

Animals↗
PubMedDate not supplied

Kinetics of simultaneous saccharification and lactic acid fermentation processes.

After pretreatment of corn cob by dilute acid, the lignocellulosic residue was used as raw materials for the simultaneous saccharification and lactic acid fermentation (SSLF). Because of the same optimal temperature and pH requirement as well as the anaerobic condition, the lactic acid fermentation is perfectly compatible with enzymatic hydrolysis of cellulosic materials. In the SSLF processes, the final concentration of lactic acid reached 33.97 g/L with a conversion ratio of 79% based on the consumed cellulose. A mathematical model is suggested to simulate the SSLF process with good agreement.

Adsorption↗