Biomedical subjects

P Li

Publications and source records attributed to P Li.

At least 271 records · Page 15Linked to original sources

PubMed1999

Neuroendocrine effects of dehydration in mice lacking the angiotensin AT1a receptor.

Angiotensin (Ang) type 1a (AT1a) receptors are critical in the control of blood pressure and water balance. Experiments were performed to determine the influence of dehydration on brain Ang receptors and plasma vasopressin (VP) in mice lacking this receptor. Control or AT1a knockout (AT1aKO) male mice were give water ad libitum or deprived of water for 48 hours. Animals were anesthetized with halothane, blood samples were collected by heart puncture, and brains were processed for Ang-receptor autoradiography with 125I-sarthran (0.4 nmol/L). Dehydration produced an increase in AT1 receptors in the paraventricular nucleus (PVN) and anterior pituitary (AP) in control mice (PVN: 70+/-16 versus 146+/-10 fmol/mg protein; AP: 41+/-7 versus 86+/-15 fmol/mg protein). No changes were noted in the median preoptic nucleus. The majority of the brain receptors were of the AT1 subtype. There was little or no specific Ang binding in AT1aKO mice and no effect of dehydration. Plasma VP levels were elevated in the halothane-anesthetized animals (>200 pg/mL) with no significant effect of dehydration. A separate experiment was performed with decapitated mice anesthetized with pentobarbital. Dehydration increased plasma VP in control mice, from 3.3+/-0.6 to 13.3+/-4.7 pg/mL, whereas no change was noted in the AT1aKO mice, 5.1+/-0.3 versus 6.1+/-0.7 pg/mL (water versus dehydration). These results demonstrate a differential response to dehydration in mice lacking AT1a receptors. There was no evidence for AT1 receptors of any subtype in the brain regions examined and no effect of dehydration on VP secretion or brain Ang receptors.

Angiotensin II↗

PubMed1999

Experience with assessing the quality of comments on clinical biochemistry reports.

We assess a previously described scoring system for the appropriateness of interpretative comments on clinical biochemistry reports over 21 distributed cases and over a group of 41 UK-based participants. The distributed cases covered a range of clinical scenarios and included pre- and post-analytical problems. The UK-based participants had all registered an interest in using this case participation for their continuing professional development; all had higher professional qualifications in clinical biochemistry, and the group included participants based in teaching hospitals and district general hospitals as well as those with a medical or a scientific background. Although the present scoring system favours participants who mention more than one possible outcome and who include several ideas for further investigation, its advantages seem to outweigh its disadvantages. The scored cases are currently unique, and are seen to be of major educational value not only by active participants but also by those who are using them for teaching or in discussion groups.

Chemistry, Clinical↗

PubMed1999

Enhancement of the nerve growth factor-mediated neurite outgrowth from PC12D cells by Chinese and Paraguayan medicinal plants.

It is very important to search for natural compounds possessing nerve growth factor (NGF)-potentiating activity. Extracts of 7 Chinese and 10 Paraguayan medicinal plants were examined for their effects on the NGF-mediated neurite outgrowth from PC12D cells to evaluate their NGF-potentiating activities. In the methanol extracts, Gymmopteris rufa (LINN.) BERNH, Ruta graveolens LINN. and Picrorhiza scrophulariiflora PENNELL markedly increased the proportion of neurite-bearing cells. In the case of ethyl acetate fractions, Equisetum giganteum LINN. produced the most powerful enhancement of the proportion of the neurite-bearing cells, and the activities were in the following decreasing order: Equisetum giganteum LINN., Gymmopteris rufa (LINN.) BERNH, Ruta graveolens LINN., and Picrorhiza scrophulariiflora PENNELL. In the water fractions, Imperata cylindrica, Ginseng Radix, Gymmopteris rufa (LINN.) BERNH, Gochnatia polymorpha (LESS) CAB and Picrorhiza scrophulariiflora PENNELL caused a weak enhancement of the proportion of PC12D cells with neurites. Of all the extracts and fractions, the methanol extract of Picrorhiza scrophulariiflora PENNELL induced the longest neurites in PC12D cells. In the ethyl acetate and water fractions of Nardostachys chinensis, long neurites were observed although only a small proportion of PC12D cells had neurites. On the other hand, in the ethyl acetate fraction of Equisetum gigantheum LINN., while the length of the neurites was short, the proportion of neurite-bearing cells was largest among all the extracts and fractions.

Animals↗

PubMed1999

Bi-directional actions of estrogen on the renin-angiotensin system.

Estrogen stimulates the renin-angiotensin system by augmenting both tissue and circulating levels of angiotensinogen and renin. We show, however, that angiotensin converting enzyme (ACE) activity in the circulation and in tissues is reduced in two animal models of postmenopausal chronic hormone replacement. We observed a reduction of ACE activity in association with a significant increase in plasma angiotensin I (Ang I) and hyperreninemia in ovariectomized monkeys treated with Premarin (conjugated equine estrogen) replacement for 30 months. Plasma angiotensin II (Ang II) levels were not increased in monkeys treated with estrogen, suggesting that the decrease in ACE curtailed the formation of the peptide. The Ang II/Ang I ratio, an in vivo index of ACE activity, was significantly reduced by estrogen treatment, further supporting the biochemical significance of estrogen's inhibition of ACE. In ovariectomized transgenic hypertensive (mRen2)27 rats submitted to estrogen replacement treatment for 3 weeks, ACE activity in plasma and tissue (aorta and kidney) and circulating Ang II levels were reduced, whereas circulating levels of angiotensin-(1-7) (Ang-(1-7)) were increased. Ang-(1-7), the N-terminal fragment of Ang II, is a novel vasodilator and antihypertensive peptide. Thus, the net balance of these effects of estrogen on the reninangiotensin vasoconstrictor/vasodilator system is to promote the anti-hypertensive effect.

Angiotensins↗

PubMed1999

[Common mutation analysis for patients found in Tianjin area with glucose-6-phosphate dehydrogenase deficiency].

OBJECTIVE: To study the types of glucose-6-phosphate dehydrogenase (G6PD) gene mutation in North China and to find the relationship between the mutations and population emigrants. METHODS: DNA samples from 22 unrelated patients(21 male and 1 female) with G6PD deficiency from Tianjin area in North China were studied for the three common mutations by using both mismatched primers mediated polymerase chain reaction/ restriction enzyme analysis and dideoxy fingerprinting methods. RESULTS: Eight patients(8/22, 36.4%) were found to have the mutation R459L(1376G-->T), and seven patients (7/22, 31.8%) were found to have the mutation R463H (1388G-->A). In three of (3/7) other seven patients (7/22), H32R(95A-->G) were detected; one patient (1/3) was identified to have H32R (95A-->G) mutation. CONCLUSION: The three common mutations in South China are also found in North China. However, most of the patients in Tianjin are also the later generations of Southern emigrants.

Asian People↗

PubMed1999

[A study on polymorphism of mitochondrial DNA D loop in the Han nationality in China].

OBJECTIVE: To investigate the polymorphism of mitochondrial DNA D loop in the Han nationality in China and the mean nucleic acid substitute frequency on each site. METHODS: A 465bp-long DNA fragment in mtDNA D loop was amplified by PCR technique and the polymorphism was analyzed by restriction fragment length polymorphism (RFLP) using 6 restriction enzymes (on 10 sites). Some samples were analyzed by direct sequencing of PCR products. RESULTS: RFLP analyses with 6 restriction enzymes on the 10 sites generated 14 restriction types. The calculated mean nucleic acid substitute frequency (based on Nei formula) on each site of mtDNA D loop in the Han nationality in China was 0.029. CONCLUSION: The mean nucleic acid substitute frequency on each site in the D loop region was 10 times as high as that in mtDNA.

Asian People↗

PubMed1999

[Mutation analysis of p16 gene in non-small cell lung carcinomas].

OBJECTIVE: To investigate the role of p16 gene in the tumorigenesis of non-small cell lung carcinomas (NSCLC). METHODS: Homozygous deletion and mutation of exon 2 of p16 genes in 40 NSCLC tissues were analyzed using PCR and dsDNA direct sequencing technique. RESULTS: In 2 NSCLC tissues, homozygous deletions of p16 gene were detected; in 14 NSCLC tissues, 19 point mutations and a frameshift were detected. CONCLUSION: Point mutations of p16 gene were frequent and might play a role in the initiation and progression of NSCLC. Nt380 in this gene was a hot spot of mutation.

Carcinoma, Non-Small-Cell Lung↗

PubMed1999

[Comparative genomic hybridization analysis of primary gastric carcinomas].

OBJECTIVE: To investigate whether unknown genes are involved in the tumorigenesis of gastric cancer. METHODS: Fourty-three primary gastric carcinomas were analyzed by comparative genomic hybridization(CGH). RESULTS: A gain in chromosome 3p(8/43), 8q(8/43), 20[20(9/43), 20p(7/43), 20q(4/43)], 12q (16/43), and 13q(12/43) was observed while a loss of 19[19(15/43), 19p (13/43)], 17[17(8/43), 17p(10/43)], 16(10/43) and 1p(11/43) was discovered. CONCLUSION: There were characteristic changes in 3p, 8q, 20, 12q, 13q, 19, 17, 16, and 1p in gastric carcinoma, and some unknown genes located in the above regions might be of importance to gastric carcinoma pathogenesis.

Chromosome Aberrations↗

PubMed1999

Effects of a 99mTc-labeled murine immunoglobulin M antibody to CD15 antigens on human granulocyte membranes in healthy volunteers.

UNLABELLED: An injectible, 99mTc-labeled, murine immunoglobulin M antibody to stage-specific embryonic antigen-1 has been developed that can localize infections by binding to CD15 glycoproteins expressed on the cell membranes of human granulocytes in vivo after systemic administration. The purpose of this study was to measure its clinical effects on healthy people. METHODS: Multiple blood samples were aspirated before and after the intravenous administration of about 125 microg antibody labeled with approximately 370 MBq (10.0 mCi) 99mTc in 10 healthy human volunteers. Complete blood cell counts were performed at each time point. Whole-body scans were acquired contemporaneously with a dual-head gamma camera. The fraction of the administered dose at each time point was quantified in 18 regions of interest. Statistical analyses included paired t tests. RESULTS: Administration was associated with a transient decrease in the concentration of red and white blood cells in the whole blood. The effect always began within 3 min of administration. Its nadir was always reached 15-20 min after administration. There was full recovery with mild overcompensation in about an hour. The hematocrit dropped by a mean of 3.8% (P<0.002), whereas the total white blood cell count fell 44.0%+/-3.1% (P<0.001). The effect was most pronounced on the number of circulating granulocytes, which fell from 5.7+/-2.1 to 3.2+/-1.3x10(3)/microL blood. The drop paralleled a decrease in the percentage of whole blood radioactivity bound to the white blood cell membranes, which peaked at 50.4%+/-7.6% at 3 min after injection and then fell to 26.1%+/-9.3% over the next 30+/-13.4 min before recovering to 40.7%+/-8.2% at 2 h. Image analysis showed that the effect was temporally associated with an increase in the amount of radioactivity within the liver and the spleen. Recovery was associated with a decrease in hepatosplenic radioactivity. No evidence of cell destruction or agglutination could be detected. CONCLUSION: This study confirmed that administration of this radiolabeled antibody is associated with a transient decrease in the number of circulating granulocytes. However, there also seems to be a secondary hemodilutionlike effect on all blood components that has not been reported previously. The effect appears to be clinically silent and very short-lived.

Adult↗

PubMed1999

[Treating women with gestational impaired glucose tolerance reduces adverse outcome of pregnancy].

OBJECTIVE: To study the treatment of women with gestational impared glucose tolerance (GIGT) in relation to outcome of fetus and newborns. METHODS: 98 women with GIGT were randomized into untreated (37 mothers) and treated groups (61 mothers) that included diet control and insulin therapy. The perinatal outcomes were compared in the two groups. RESULTS: The incidence of macrosomia (P < 0.01) and fetal distress (P < 0.05) was found to be significantly higher in the untreated group when compared with the treated group. The prevalence of neonatal metabolic complications in the untreated group was higher than that of the treated group as well. CONCLUSION: Treatment of women with GIGT will reduce adverse outcome in pregnancy.

Adult↗

PubMed1999

[Clinical observation of hysteroscopic electric resection: an analysis of 36 patients with abnormal uterine bleeding].

OBJECTIVE: To assess the efficacy and influences of hysteroscopic electrosurgery in treating abnormal uterine bleeding (AUB). METHODS: 36 women with AUB received hysteroscopic transcervical resection of the endometrium or intrauterine lesions with a continuous flow resectoscope. RESULTS: The complications rate was 8.3%. 32 patients were followed for 4 to 12 months. Menstrual symptoms ameliorated in 82.4% of the patients. 5.9% of the women became amenorrhoeic. 58.8% had only spotting, 17.6% recovered normal period. 6 out of the 8 cases with dysmenorrhea had relieved their pain. Satisfactory rate of the procedure was 76.5%. Two patients received hysterectomy later for recurrent uterine bleeding. CONCLUSION: Hysteroscopic electrosurgery is an effective procedure in treating abnormal uterine bleeding. But its long-term efficacy is yet to be identified. When improving the technique and basic knowledge, the indications should be given appropriatly.

Electrosurgery↗

PubMed1999

[The coherence analysis between neuronal discharge in the rostral ventrolateral medulla and the cardiovascular activity in rats].

To analyze the coherence between neuronal discharges (ND) in the rostral ventrolateral medulla (RVLM) and the cardiovascular activity, we observed the neuronal discharge in RVLM responding to electric stimulation of the defense area of the mid-brain. Fast Fourier transform (FFT) was performed to analyze the coherence between the signals of ND and blood pressure to determine if the ND were cardiac rhythmic. The coherence between ND variability (NDV) and heart rate variability (HRV) was also analyzed. The results showed: (1) majority of the neurons (67%) were excited responding to electric stimulation in the defense area of the mid-brain; (2) the electric activity of about 70% of the neurons were substantially inhibited by administration of phenylephrine; (3) 64% of the neurons were actively synchronous with cardiac cycle; and (4) significant coherence between NDV and HRV in HF component was shown in a half of the neurons (50%). The coherence analysis thus provides a new tool to investigate the regulation of the autonomic nervous system.

Animals↗

PubMed1999

[Inhibitory effect of electroacupuncture on the cardiovascular response evoked by applying bradykinin on the gallbladder].

The effects of electroacupuncture (EA) on the pressor response and reversible myocardial dysfunction induced by application of bradykinin (BK) on the gallbladder were studied in cats anesthetized with alpha-chloralose. The cardiovascular responses evoked by application of BK included a pressor response, an increase of LVP and its dP/dtmax, tachycardia and a decrease of local wall motion of the left ventricle with a supplying branch of the left anterior descending coronary artery ligated beforehand. Following EA of bilateral Neiguan acupionts, the pressor response of BK was inhibited, while the regional left ventricle myocardial dysfunction was alleviated significantly. The effects of EA were reversed by i.v. injection of naloxone (0.4 mg/kg). Our results indicate that EA has an inhibitory effect on the BK-induced pressor and ischemic dysfunction, which may be related with endogenous opioid peptide.

Animals↗

PubMed1999

Interaction between gene p53 and oncogene mdm2 in human glandular lung cancer cell line GLC-82.

OBJECTIVE: To study the interaction between oncogene mdm2 and wp53 in human glandular lung cancer cell line GLC-82. METHODS: By lipofectamine-mediated DNA transfection, wp53 and mdm2 were transfected separately or co-transfected into GLC-82 cells via retrovival vector pDOR-neo, a carrier of wp53 and mdm2. RESULTS: The growth of GLC-82 cells was blocked and their DNA synthesis inhibited by wp53, its colony-forming rate in soft agar culture and the tumorigenicity in nude mice declined and mdm2 antagonized the function of wp53. CONCLUSION: After the recombinant vector pDOR-mdm2 was transfected into GLC-82 cells containing wp53, mdm2 partially deprives wp53 of its function of inhibiting the growth of GLC-82 cells.

Adenocarcinoma↗

PubMed1999

[The effects of twin-block magnetic appliance on the early skeletal Class III malocclusion].

OBJECTIVE: The aim of this study was to evaluate the effect of magnetic functional and orthopedic approach on treatment of early skeletal class III malocclusion. METHODS: A new type of magnetic twin-block appliance (TMA) was developed and used on 32 growing subjects with skeletal class III malocclusion. RESULTS: The class III dentofacial profile significantly improved and class III molar relationship was corrected in most cases. CONCLUSION: The Nd2-Fe14-B TMA could be used as effective orthopedic approach in treating class III malocclusion, which had many advantages, such as force prediction, well-controlled anchorage, small and comfortable design of appliance and good cooperation from patients.

Adolescent↗

PubMed1999

[A clinicopathological study of pancreatoblastoma].

OBJECTIVE: To investigate the clinicopathological, immunohistochemical features and the histogenesis of pancreatoblastoma (PB) in 14 pediatric cases, including 9 male and 5 female patients, their age ranged from 1.5 to 8 years with a mean of 4.4 years. METHODS: Routine pathological, histochemical, and immunohistochemical methods were utilized to analyse the PB specimens. RESULTS: Tumors of 6 patients had metastasized to the liver, spleen and lymph nodes, 8 patients were alive 10 months to 105 months after diagnosis. Histologically, the tumors were composed of dense epithelial elements separated by fibro-stromal tissue, resulting in a nesting or organoid pattern. Immunohistochemically and histochemically, the tumors exhibited acinar, endocrine and ductal differentiation. The positive rates for were: CK 100%, EMA 86%, NSE 79%, CEA 71%, SYN 64%, CgA 43%, alpha1-AT 57%, PAS 100% and mucicarmine 57%. CONCLUSIONS: PB is the most common malignant pancreatic neoplasm of childhood. PB arises from primitive pluripotential cells capable of differentiating into 3 pancreatic cell types: acinar, endocrine and ductal. The prognosis is better than pancreatic carcinoma in adults.

Carcinoembryonic Antigen↗

PubMed1999

[Study of BAEP, TCD and neck rotation test in vertebrobasilar-artery insufficiency patients].

Forty patients with vertebrobasilar-artery insufficiency(VBI) were checked by BAEP and BAEP together with neck-rotation test. Their positive rates were compared with those of TCD. The results showed that: 1. the positive rate of BAEP was 50%, lower than that of TCD; 2. after neck rotation test, the positive rate of BAEP increased from 50% to 86.3%. The results suggest that BAEP together with neck rotation test can obviously increase the positive rate of BAEP. The method is simple and effective in clinical application.

Adult↗

PubMed1999

[Stress and dietary salt intake in the pathogenesis of hypertension: role of the renal and sympathetic nervous system].

Using the methods of electrophysiology, biochemistry, radioimmunoassay, and electron microscopy, changes of sympathetic nervous system and renal function in hypertensive SD rats induced by stress and high-salt intake were investigated. The results are as follows: (1) Renal plasma flow (RPF) and urinary sodium excretion obviously increased in salt-loading rats. Stress could result in marked reduction of RPF. (2) Electron micrography showed a dramatic increase in cell and mitochondrial volume in the proximal and distal convoluted tubules of high-salt diet rats. After stress of two weeks, the cells of the tubule became atrophic and mitochondrial volume decreased. (3) The same recovery from the declining renal cortical Na-K-ATPase activity in high-salt diet rats could be observed by maintained stress. (4) Low frequency (0.2-0.9 Hz) of BP variability was higher in stress rats as compared to control. (5) Both plasma renin activity (PRA) and angiotensin II (ANG II) levels increased in stress rats, but the decrease in high-salt diet rats gradually reached the high level of the former in two weeks. (6) Increase of BP, fall in RPF, or augment in PRA and ANG II were not observed in stress rats subjected to bilateral renal denervation. The above results indicate that the renal mechanism mediated by increased renal sympathetic nervous system plays an important role in stress- and salt-induced hypertension pathogenesis.

Animals↗