Biomedical subjects
Publications and source records attributed to A Li.
This paper presents an experimental study on the growth of Panax ginseng seeds from two different areas during their seedling stage in Beijing. The result shows that the seed produced in Ji'an area is better fit for planting in the northern part of China.
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The effects of the dissociative anaesthetic, ketamine on GABA-evoked changes in the excitability of myelinated fibers of dorsal and ventral roots of isolated bullfrog sciatic nerves were examined. Ketamine alone (0.01-1000 microM) evoked small increases (less than 5%) in dorsal root fiber excitability, as reflected in the half-maximal A-fiber compound action potential when concentrations were greater than 10 microM; with greater than or equal to 0.1 microM even larger increases (greater than or equal to 10%) were elicited in the ventral root fibers. As well, the increases evoked by greater than or equal to 10 microM ketamine were followed by graded decreases. 0.1 and 10 microM ketamine, concentrations which by themselves had small or no effect, produced a dose-dependent depression of the large increases in excitability which are induced by activation of GABA receptors. In the presence of ketamine GABA concentration-response curves of the dorsal root fibers showed depression of the maximal response, while those of the ventral root fibers were shifted to the right. This apparent antagonism of GABA responses by ketamine may arise from blockade of receptor-mediated effects (e.g. K+/Cl- currents and/or secondary depolarization from K+ accumulation), but could also be caused by a selective potentiation of hyperpolarizing receptors.
Thromboxane (TXA2) and prostacyclin (PGI2) levels, circulatory platelet aggregate ratios (CPAR), CPK, LDH, GOT, platelet counts, blood viscosity, cortisol and urine epinephrine contents were determined in 42 burned patients who were divided into two groups: Group I control (n = 34) and Group II (n = 8) treated with TXA2 synthesis inhibitor, anisodamine. It was found that in controls, both TXA2 and the TXA2/PGI2 ratio increased significantly. There was no marked difference in PGI2 levels between the two groups. Platelet counts and CPAR decreased, while blood viscosity, CPK, LDH, GOT, cortisol and epinephrine in the controls were all significantly higher than those found in Group II patients. All these findings suggested that the changes of TXA2 and the TXA2/PGI2 ratios played an important role in the haemodynamics and haemorrheology in burn shock. The TXA2 synthesis inhibitor, anisodamine, showed beneficial effects by restoring the haemodynamic and rheological disturbances towards normal by virtue of their ability to induce vascular constriction, platelet aggregation, cellular destruction, destabilization of membranes and release of chemical mediators (including enzymes). Furthermore, at 1-3 days postburn, the levels of CPK, LDH and GOT in controls were higher than those measured at 12 h postburn, but this phenomenon was not marked in the treated group, suggesting that after resuscitation, reperfusion damage had occurred and TXA2 might be responsible for the damage. It is assumed that anisodamine could protect tissues from reperfusion damage. The findings also suggested that anisodamine could quicken the restoration of neuroendocrine disturbance initiated by shock (stress).
Due to the nature of three-dimensional Fourier transform (3-DFT) data acquisition in magnetic resonance imaging (MRI), the spatial relation between a resolved volume element (a voxel) and the object can be manipulated easily. Those manipulations have practical consequences in terms of registering slice positions with respect to features of interest in producing oblique reformatted images where volume resolution is preserved, and in generating reformatted images that project the viewing plane onto a surface through the object that has an arbitrary shape.
An anaerobic, mesophilic, spore-forming, cellulolytic bacterium was repeatedly isolated from a wood-fermenting anaerobic digester. Cells of this organism were gram-positive rods, motile with a bundle of polar flagella, and formed subterminal oblong spores. The colonies in agar had an irregular shape with many platelike structures and were greyish white. Cellulose, xylan, and cellobiose served as substrates for growth. Acetate, propionate, butyrate, isobutyrate, isovalerate, lactate, succinate, H2, and CO2 were products of cellobiose fermentation. The optimal temperature and pH for growth were 35 degrees C and 7, respectively. The DNA composition was 40 mol% G + C. The name Clostridium aldrichii sp. nov. is proposed. The type strain is P-1 (= OGI 112, = ATCC 49358).
A smoke inhalation model was created in 22 adult male sheep with pine smoke inhalation through an endotracheal tube for 6 min. Arterial blood gases, HbCO, HbO2 and pulmonary compliance (Cdyn) were monitored, and the morphology of the tracheobronchial tree and pulmonary parenchyma were studied by light and electron microscopy. Severe carbon monoxide poisoning with fatal levels of HbCO (greater than 50 percent) was found at the end of smoke inhalation. Acute respiratory distress, progressive hypoxemia, decreased pulmonary compliance and increased P(A-a)O2 and Qs/QT occurred after injury. Tracheobronchial blockade by pseudomembrane cast, pulmonary edema, atelectasis and necrosis of pulmonary epithelia were demonstrated pathologically. The mechanisms of CO poisoning and ARF are discussed.
This paper reports the determination methods for calcium carbonate, trace elements and amino acids in the traditional Chinese medicine Os Sepiae. The data provide a reference for the quality control of the drug.
The human teratocarcinoma cell NTERA-2 cl. D1 (NT2/D1) is a cloned embryonal cancer cell line that differentiates into a neuronal phenotype and other cellular lineages after treatment with retinoic acid (RA). We examined the regulated expression of growth factors and proto-oncogenes in NT2/D1 cells. We studied RNA levels after six days of RA treatment to assess gene expression coincident with observed morphologic differentiation. Three growth factors were markedly down-regulated following RA treatment: Hst-1/kFGF and TGF-alpha expression became undetectable by Northern analysis and bFGF expression was substantially reduced. Minimal decline was seen for c-myc, N-myc, c-fos, and c-myb. Increased expression with differentiation was seen for the human homeotic genes Hox 2.1 and Hox 2.2. Assay of RNA levels daily after one to six days of RA treatment showed that the growth factor down-regulation inversely correlated with the homeotic gene up-regulation. Nuclear run-on studies showed low transcriptional rates for these homeotic genes, Hst-1/kFGF, and TGF-alpha that did not measurably change with RA treatment. To explore whether these regulated genes in NT2/D1 play a role in human testicular cancer, we examined RNA levels in a panel of human germ cell cancer lines. Hst-1/kFGF and bFGF are commonly expressed in five of seven male germ cell cancer lines. These data show that specific proto-oncogenes and growth factors are down-regulated with RA treatment of the NT2/D1 cell and that some of these regulated genes are often expressed in human germ cell cancer lines.
The phenotypes of lymphoid cells from twelve patients with mycosis fungoides (including 5 patients in the tumor stage and 7 in the pretumor stage) were determined immunohistochemically using anti-thymocyte monoclonal antibodies (HIT1, HIT2, and Leu 6). The results showed significant differences between the numbers of HIT1 and HIT2 positive cells in tumor and pretumor stage lesions, indicating that these two monoclonal antibodies may be of help in the staging of mycosis fungoides and in making a prognosis. Also, we found that some Leu 6 (+) cells in tumor stage lesions were round or oval in shape without dendritic processes, suggesting that they may be immature lymphocytes.
The human teratocarcinoma NTERA-2 cl. D1 (NT2/D1) cell is a cloned multipotential embryonal cancer cell line that differentiates into a neuronal phenotype and other cellular lineages with retinoic acid (RA) treatment. Here we report that mRNA for the transforming growth factor-alpha is expressed in these RA-untreated cells and that RA-treatment results in a reduction of mRNA expression within 24 hr of treatment. In total cellular RNA, TGF-alpha mRNA is not detectable by Northern analysis at 6 days when there is increased expression of the human homeotic genes Hu-1 (Hox 2.1) and Hu-2 (Hox 2.2), known markers of RA response in NT2/D1 cells. RA treatment also causes a marked reduction in cloning efficiency and tumorigenicity of these cells. The addition of TGF-alpha or EGF (epidermal growth factor) protein to RA-untreated NT2/D1 cells augments soft agar cloning under limited fetal calf serum conditions. Blocking monoclonal antibodies directed against the EGF receptor (EGFr) can prevent this augmentation. We conclude that TGF-alpha expression inversely correlates with the state of RA-induced differentiation of this human teratocarcinoma cell and that TGF-alpha and EGF proteins are stimulatory growth factors in NT2/D1 cells under these culture conditions.
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