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Biomedical subjects

L M Zhang

Publications and source records attributed to L M Zhang.

At least 73 records · Page 4Linked to original sources
PubMed1992

The ultrastructure of the abdominal trumpet gland and antennal ascoid and papilla of Chinius junlianensis Leng, 1987 (Diptera: Psychodidae).

When viewed with a light microscope, each trumpet gland of Chinius junlianensis appears as 15-20 small trumpet-shaped structures with their narrower proximal ends clustered together on the surface of a tergite. By scanning electron microscopy (SEM), however, the glands appear to be abdominal exosecreting organs with honeycomb-like openings at the inter-tergal junctions 3/4 and 4/5. Although the other ascoids of C. junlianensis are round in cross-section, each of those distal to antennal segment 8 is roughly triangular, with three ridges and three concave surfaces, and has a large oval depression at its base. The basal ridge has three to five rows of denticulations. The antennal papilla is oval, with a comb-like fence of four to five thin pointed processes on each side and a stout central spine.

Abdomen↗
PubMed1992

Stimulation of calcium influx in HL60 cells by cholesteryl-modified homopolymer oligodeoxynucleotides.

Cholesteryl-modified 15-mer homopolymers of cytidine and thymidine phosphodiester oligodeoxynucleotides (chol-OdC15 and chol-OdT15), but not chol-modified heteropolymeric oligos or chol-modified phosphorothioate oligos, were found to increase cytosolic free Ca2+ in HL60 cells. A flow cytometer and the calcium-sensitive dye indo-1 were used to make multiparameter measurements on the HL60 cells. Chol-OdC15 (5-10 microM) triggered a rapid increase (within 1 min) in [Ca2+]i, with a subsequent slow decline to baseline over 15 min in the continuous presence of agonist. The effect was preserved after unloading the intracellular Ca2+ stores with caffeine and ryanodine. The effect was not sensitive to membrane depolarization by KCl (60 mM) or nimodipine, a dihydropyridine calcium channel antagonist. An increase in [Ca2+]i was absent in a Ca(2+)-free solution and was inhibited by the inorganic Ca2+ channel blocker Cd2+. The results suggest that Ca2+ influx activated by the chol-oligomer is probably mediated by receptor-operated Ca2+ channels. This effect may be due to direct binding of the chol-oligo to the channel or to induced conformational changes due to modification of the local microenvironment.

Base Sequence↗
PubMed1992

[Correlativity of plasma endotoxin, plasma fibronectin and common bile duct pressure in severe acute cholangitis].

On the basis of common bile duct pressure measurement (CBDP) in 18 patients of severe acute cholangitis, plasma endotoxin (ET) was determined by modified synthetic chromogenic limulus amebocyte lysate assay and plasma fibronectin (FN) was detected with Laurell's rocket immunoelectrophoresis. CBDP was 2.23 +/- 0.49 KPa in patient group. There was striking positive correlation between ET and CBDP. Preoperative ET was 202.73 +/- 88.57 ng/L in patient group which was much higher than 15.47 +/- 7.38 ng/L in the control (P less than 0.001). Preoperative FN was 141.77 +/- 82.37 mg/L in the patient group which was lower than 317.21 +/- 12.57 mg/L in the control (p less than 0.001). Statistical differences could be noticed in postoperative ET and FN between the survivor and the dead. The study suggested that plasma ET levels are greatly influenced by pressure gradient of bile duct, dynamic observations of ET and FN levels are helpful to monitor disease course and predict prognosis.

Acute Disease↗
PubMed1991

Chronic administration of growth hormone-releasing factor increases wound strength and collagen maturation in granulation tissue.

The effects of chronic administration of growth hormone-releasing factor (GRF) on wound healing were studied in rats. Cutaneous wound strength was measured by tensometry at 5, 10, and 14 days postwounding in rats implanted with a slow-release pellet which contained a compressed mixture of a fatty acid and [desamino Tyr1, D-Ala2, Ala15]hGRF(1-29)NH2 or the fatty acid alone. There was a significant increase in wound tensile strength in GRF-treated rats compared to controls at each measurement: Day 5, 130 +/- 12 vs 97 +/- 14 g; Day 10, 402 +/- 18 vs 280 +/- 11 g; Day 14, 830 +/- 17 vs 614 +/- 14 g (P less than 0.01 for each value). Granulation tissue obtained from subcutaneously implanted polyvinyl alcohol sponges encased in silicone tubing was also studied. The amount of collagen deposited in the granulation tissue was estimated by measuring the hydroxyproline (Hyp) content of sponges retrieved 5, 10, and 14 days postinsertion from GRF-treated and control rats. Hyp content (nmole/mg sponge) was similar in both treated and control animals at each measurement: Day 5, 1.7 +/- 0.2 vs 2.2 +/- 0.2; Day 10, 31.9 +/- 4.1 vs 26.7 + 0.4; and Day 14, 41.6 +/- 7.3 vs 38.5 +/- 4.4. Hyp/proline, Hyp/glycine, and glycine/total amino acid ratios, evaluated after 10 days, were also similar in both groups. Collagen from the granulation tissue of sponges retrieved after 14 days from treated and control rats was studied by electron microscopy (magnifications, 7,100 and 22,720).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Calcium metabolism and osteopathy in diabetes mellitus.

To assess the changes of calcium metabolism and osteopathy in patients with diabetes. Serum Ca, P, AKP, PTH, CT, plasma fasting blood glucose (FBG) and HbA1 as well as X-ray film of the lumbar spine were measured in 30 diabetes patients; 11 were IDDM and 19 were NIDDM as compared to controls matched for age and sex. There were no significant differences in Ca, P, and CT values in serum between the IDDM and NIDDM patients and controls, whereas the serum levels of PTH and AKP were significant increased in IDDM patients. The incidence of osteoporosis which was shown by X-ray film in NIDDM patients was higher than in those of controls. No correlation between PTH value and osteoporosis or clinical control of diabetes was observed.

Adult↗
PubMed1991

[Antagonistic effect of phencyclidine on cerebral ischemic damage of rats].

Dynorphin and catecholamine were measured in ischemic rat produced by four-vessel (2 vertebral arteries and 2 common carotid arteries) occlusion for 10 min. The results showed that: (1) The contents of dynorphine (pg/mg tissue) in cerebral cortex were 5.5 +/- 0.6 (n = 7) in normal rats and decreased to 4.9 +/- 0.5 (n = 9, P less than 0.05) in cerebral ischemic rats; with immediate ip phencyclidine (1-(1-phenylcyclophexyl)piperidine, PCP, 1 mg.kg-1), the contents of dynorphin were increased to 5.3 +/- 0.4 (n = 5, P less than 0.05 vs the ischemic rats). (2) The contents of DOPAC (pg/mg tissue) in cerebral cortex were 38 +/- 6 (n = 7) and increased to 120 +/- 60 (n = 5, P less than 0.05) in 10 min cerebral ischemic rats; with immediately ip PCP (1 mg.kg-1), the contents of DOPAC were decreased to 26 +/- 13 (n = 7, P less than 0.05 vs the ischemic rats). (3) The release of DA (pg/mg tissue) in cortical slices in vitro, in high K+ solution were 24 +/- 3 (n = 5) and significantly increased to 57 +/- 15 (n = 5, P less than 0.05) in ischemic rat brain slices; with immediate ip PCP (1 mg.kg-1), the contents of DA were decreased to 38 +/- 10 (n = 5, P less than 0.05 vs the ischemic rats). These results suggest PCP play an antagonistic role in cerebral ischemic damage of rats.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

A study of phlebotomine sandflies (Diptera: Psychodidae) in Yunnan Province, China. I. Phlebotomine sandflies of northeastern and western Yunnan.

From August to September, 1984 phlebotomine sandflies were collected with light-sticky traps by the authors in the following places viz., Weixin, Yanjian and Huize Counties, North-eastern Yunnan; Xiaguan, Baoshan, Shidian, Longling, Lùxi, Ruili, Yingjiang and Tengchong Counties, western Yunnan. A total of 9 species had been identified. Their systematical catalogue and zoogeographical distribution were given.

Animals↗
PubMed1991

A preliminary isoenzyme study on five species of phlebotomine sandflies in China.

During June to August, 1987, six species of phlebotomines were collected by aspirator from four localities in Beijing, Nanjiang and northwestern Sichuan Province. After morphological identification, five species viz., Phlebotomus chinensis, P. sichuanensis, Sergentomyia zhengjiani, S. khawi and S. squamirostris were studied starch gel electrophoresis in 10 enzymes for isoenzyme characterization. Among which four enzymes (MDH, PGM, PGI and alpha-GPD) showed varying degrees of differences. The characteristic enzyme locus of PGM can be used to identify P. sichuanensis (Sichuan strain) from P. chinensis (Sichuan and Beijing strains) two vectors of Chinese visceral leishmaniasis, the pharyngeal armatures and spermathecae of which are morphologically resemble in females. The locus of PGM for genotype AA is over 77% in P. chinensis compared with 8.3% in P. sichuanensis and genotype DD is 75% in P. sichuanensis compared with negative in P. chinensis. Distinct enzymatic differences were demonstrated between genera Phlebotomus and Sergentomyia. The alleles of MDH-1 were 100 and 95 in genus Phlebotomus and Sergentomyia respectively, meanwhile in alpha-GPD the alleles were at 100 and 97 respectively except S. squamirostris. In PGI it showed polymorphic with two loci and more alleles in Phlebotomus and monomorphic with only one locus in Sergentomyia. The similar enzyme phenotype between morphologically distinct species, S. zhengjiani and S. khawi shown that the uncorrespondence between morphological and genetic characters in evolution is present in some cases of phlebotomine such as in other insects.

Animals↗
PubMed1991

Experimental verification of effectiveness and harmlessness of the Qigong maneuver.

A series of experiments involving the Qigong (Q-G) maneuver were conducted after our preliminary studies in 1986. Eighteen active fighter pilots served as subjects. After mastery of the Q-G maneuver in 5-7 sessions of training, tests at +1 Gz further verified that the blood pressure raising effect of this maneuver has the characteristics of rapid rising, minimal fluctuation and being readily maintained. The 18 subjects then underwent centrifuge tests. The tolerance to Rapid Onset Rate (ROR) (1 G/s) G-load in a relaxed, unprotected condition was 3.82 G on average; performing the Q-G maneuver, the tolerance rose to 6.64 G, an improvement of 2.82 G. One to two days later, 5 subjects with anti-G suits on and performing the Q-G maneuver tolerated 7.80 G on average (ROR 1 G/s), a gain of 3.95 G. Another 9 subjects performing the Q-G maneuver endured high sustained G (HSG) (ROR 3 G/s) of 6.5 G for 74.4 s on average (max 96 s) and 3 subjects endured HSG of 7.0 G for 57 s on average (max 82 s). During centrifuge tests, recorded physiological values showed good tolerance of the subjects; the respiratory pattern was basically different from that of M-1 or L-1 maneuvers. In further testing the harmlessness of the Q-G maneuver, gas metabolism, ear lobe oximetry and 8-channel EEG were carried out on these subjects. All these indices plus close monitoring during centrifuge tests proved that the Q-G maneuver does not lead to hypoxia or hyperventilation. It has been shown that the Q-G maneuver is an innovative G-protective maneuver that is remarkably effective, theoretically interesting, reliable, and practical. Its mechanism warrants investigation.

Adult↗
PubMed1990

Simultaneous electric activities of pain-excitation and pain-inhibition neurons in nucleus parafascicularis of thalamus in rats during acute morphine tolerance.

When acute morphine-tolerated rat was administered by ip morphine (10 mg/kg) which was effective before the acute tolerance to morphine, both the inhibitory effect of morphine on the electric discharges of pain-excitation neurons (PEN) in nucleus parafascicularis (PF) and the excitatory effect of morphine on the electric activities of pain-inhibition neurons (PIN) were simultaneously weakened, or even vanished. If a large dose of morphine (20 mg) was given ip, the modulating action of morphine on simultaneous electric discharges of PEN and PIN reappeared. It is obvious that the phenomenon of acute morphine tolerance and the antagonism to morphine tolerance can be explicitly expressed on the level of central neurons.

Animals↗
PubMed1989

Metoprolol and mephenytoin oxidation polymorphisms in Far Eastern Oriental subjects: Japanese versus mainland Chinese.

We examined genetically determined oxidation polymorphisms of metoprolol and mephenytoin in 200 unrelated, healthy Japanese subjects and in 98 mainland Chinese subjects simultaneously. This examination was done according to the respective reported phenotyping criteria by use of the urinary metabolic ratio of metoprolol and of the percentage of excretion of 4-hydroxymephenytoin 8 hours after dose administration. The frequencies of occurrence of poor metabolizers (PMs) in the Japanese versus the Chinese subjects were 0.5% versus 0% for metoprolol and 22.5% versus 17.4% for mephenytoin, respectively. There were no statistically significant differences in these frequencies between the two Oriental populations. However, Chinese extensive metabolizers (EMs) showed a significantly lower excretion of alpha-hydroxymetoprolol (p less than 0.01) and 4-hydroxymephenytoin (p less than 0.001) than that of Japanese EMs, and the mode of the distribution histogram of the Chinese EMs for the two test probes was skewed compared with that of the Japanese EMs. The findings indicate that the two Far Eastern Oriental subject groups have a lower frequency of PM phenotype of debrisoquin/sparteine-type oxidation and a greater incidence of PM phenotype of mephenytoin oxidation compared with the respective frequencies reported from white subjects. However, the explanation for the observation that the metabolic capacities of the test drugs differed between the EMs of the two populations who had a similar ethnic origin and who resided in the same geographic area remains obscure.

Adolescent↗
PubMed1989

[Phencyclidine receptors in porcine cerebral arteries].

A specific, saturable, reversible, and selective binding site with Kd = 87 +/- 33 nmol/L, Bmax = 0.78 +/- 0.11 pmol/mg protein was detected in the binding of [3H] phencyclidine (PCP) to porcine cerebral blood vessels. Only ligands of PCP/sigma series were able to bind to the PCP receptors. [3H]PCP bound to its receptors was not displaced by etorphine or norepinephrine 0.1 mmol/L. A specific [3H]PCP binding site was found in porcine brain with Kd = 75 +/- 34 nmol/L, Bmax = 0.61 +/- 0.23 pmol/mg protein. Bioassay in vitro showed PCP enhanced the perfusion pressure of porcine cerebral blood vessels in a dose-dependent manner. This study provides direct evidence for PCP receptors on cerebral blood vessels, and suggests that PCP may produce cerebral vasospasm via PCP receptor interaction.

Animals↗
PubMed1989

[Autoradiographic study on etorphine and phencyclidine specific binding sites in rabbit mesenteric artery].

Autoradiography was used to study the localization of kappa and PCP/sigma receptors in the blood vessels. Slices of rabbit mesenteric arteries were incubated with 0.4 nmol/L [3H]etorphine or/and 10 mumol/L etorphine for 45 min at 25 degrees C, or incubated with 5.2 nmol/L [3H]PCP or/and 20 mumol/L PCP for 60 min at 4 degrees C. Then, slices were covered with emulsion coated coverslip and kept for 8-10 wk at 4 degrees C. The results were as follows: Microscopy Autoradiographic analysis indicated that etorphine and PCP specific binding sites were both located in the outer-layer and the smooth muscle of the artery. However, most of these binding sites were lost in the 6-OHDA pretreated arteries in which the adrenergic nerve endings were destroyed. Microspectrophotometry The absorbance (A) of [3H]etorphine autoradiographic density for total binding (TB) and nonspecific binding (NSB) in control group were 0.416 +/- 0.056 and 0.044 +/- 0.011, respectively (P less than 0.01), and for TB after incubation with 6-OHDA was 0.068 +/- 0.013 which was different from the A value of TB in the control (P less than 0.01). The A value of [3H]PCP autoradiographic density for TB and NSB in the control were 0.546 +/- 0.087 and 0.023 +/- 0.060, respectively (P less than 0.01), and for TB after incubation with 6-OHDA was 0.065 +/- 0.015 which was significantly less than that of TB in the control group (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

N-acetylation phenotyping with dapsone in a mainland Chinese population.

1 The N-acetylation of dapsone (DDS) was studied in 108 unrelated Chinese subjects residing in the mainland of China. 2 The frequency of slow acetylators determined using the plasma monoacetyldapsone to DDS ratio (MADDS/DDS, slow acetylators less than 0.30 and rapid acetylators greater than 0.35) at 3 h after an oral dose of DDS (100 mg) was 13.0% (14 of the 108 subjects) with a 95% confidence interval of 7.9 to 20.6%. 3 The mean plasma concentration of MADDS was about three times lower in the slow than in the rapid acetylators and there was a highly significant correlation (rs = 0.886, P less than 0.001) between plasma MADDS concentration and acetylation ratio. 4 Urinary acetylation ratios (MADDS/DDS) and cumulative urinary excretion of MADDS were significantly (P less than 0.001) lower in slow acetylators compared with rapid acetylators. In addition, there was a significant relationship (rs = 0.510 to 0.718, P less than 0.001) between plasma and urinary acetylation ratios. However, the distribution of the urinary acetylation ratio was not bimodal. 5 The urinary acetylation ratio after an oral dose of DDS is not a discriminative index for determining acetylation phenotype.

Acetylation↗
PubMed1988

A preliminary report on a new anti-G maneuver.

Inspired by Traditional Chinese Medicine and Qigong, we designed a new anti-G maneuver, the Q-G Maneuver, which has proved promising. This maneuver consists of volition mobilization, stepwise tensing of leg and abdominal muscles, and maintenance of a shallow thoracic respiration throughout. It was tested on 24 pilots on the ground and 3 pilots on a centrifuge. All pilots were monitored with heart level blood pressure, oximetry, ear lobe pulse, CO2 concentration in exhaled gas, EEG and ECG; in centrifuge runs, peripheral vision was also monitored. Blood pressure was maintained at 180-240 mm Hg for more than 30 s without fatigue. On the centrifuge, the pilots tolerated a G load 2.25-3.0 G higher than without the maneuver, without any visual disturbance. Oximetry readings were 96-97%, and there was no evidence of hyperventilation. The ear lobe pulse was even enhanced during G load with the maneuver. Follow-up visits to 18 out of 24 pilots with 455 inflight applications of the maneuver showed that the maneuver is feasible and can be used effectively during high-G load.

Aerospace Medicine↗