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Biomedical subjects

Z M Liu

Publications and source records attributed to Z M Liu.

At least 55 records · Page 3Linked to original sources
PubMed1991

A study on the circadian rhythm of glucocorticoid receptor.

Circadian rhythm in glucocorticoid receptor (GR) was studied in the rat liver and human peripheral leukocytes. For rats exposed to a natural environmental photic cycle or a 12L:12D artificial light regime, peak values of hepatic GR were detected between 23:00 and 02:00 h. Except for a 4-hour advancement of the peak, a similar circadian rhythm of hepatic GR was detected in rats reared under a reversed lighting regimen (12D:12L; lights on between 18:30 and 06:30 h). In human leukocytes, the peak value of GR was found to parallel that of plasma cortisol with high and low values detected at 04:00-08:00 h and 23:00-24:00 h, respectively. In patients suffering from Cushing's syndrome, the circadian rhythm of plasma cortisol either disappeared or was inverted while that of GR did not significantly deviate from the normal subjects. For apoplexic patients with lesions localized to the base of the brain as indicated by computerized tomography, the diurnal variation of GR was abolished. Conversely, diurnal rhythmicity persisted in apoplexy patients whose lesions were in the cerebral cortex. Thus, we postulated that the circadian modification of GR was independent of the diurnal fluctuations in plasma cortisol level or the circadian variations in environmental lighting and that the rhythmicity might be regulated by the 'circadian pacemaker' located in the human basal brain. These diurnal variations in GR might serve to coordinate the reactivity of the target cells to cortisol because the diurnal rhythms of a GR-mediated response, the fractional inhibition of chemotactic migration rate of polymorphonuclear leukocytes by cortisol, were found to be synchronous with those of GR.

Adult↗
PubMed1991

[Mechanism of enhancement of bleomycin A5 antitumor activity by verapamil].

The mechanism of enhancement of Bleomycin A5 antitumor activity by verapamil was explored by flow cytometry and tracing the radiolabelled bleomycin A5 in vivo. Verapamil was found to increase the G2 blocking effect of bleomycin A5 prominently in mouse S-180 and human HEP-2 cell lines. The distribution of 57Co-bleomycin A5 in mice bearing S-180 sarcoma was changed by verapamil and accumulation of the drug in tumor was increased. In contrast, the labelled drug in the lung was decreased. It seems that the effects of verapamil in enhancing the antitumor activity of bleomycin A5 are to increase the accumulation of the drug in tumor cells and enhance the G2 blocking effect of the drug in cell cycle.

Animals↗
PubMed1991

[Regulatory effect of insulin on glucocorticoid receptor in human peripheral leukocytes].

The regulatory effect of insulin on the specific binding power of glucocorticoid receptor (GR) of human leukocytes was assessed by the unoccupied receptor sites capable of combining with [3H] labelled dexamethasone measured at 3 and 24 h after incubation with various concentrations of insulin added to the medium. After 3 h incubation the specific binding power with [3H] Dex was decreased by 23.3 +/- 10.0, 32.2 +/- 13.2 and 54.3 +/- 9.2% (P greater than 0.05, P greater than 0.05 and P less than 0.01 as compared with the control value of 100 in the absence of insulin) respectively in the presence of 20 mU/L (physiological testing concentration), 200 mU/L (physiological upper limit) and 2,000 mU/L (pharmacological concentration) insulin in the incubation medium. After 24 h incubation the decrease of these values increased respectively to 43.5 +/- 19.0, 56.1 +/- 20.7 and 80.2 +/- 15.5 (P less than 0.05, P less than 0.01 and P less than 0.01 compared with control). Thus the inhibitory effect of insulin on the GR binding power is both dose- and time-dependent, which strongly suggests that GR is tonically controlled by insulin concentration change under physiological conditions.

Cells, Cultured↗
PubMed1991

[Clinical and experimental study on cerebral thrombosis treated with antithrombotic xinmaining].

Antithrombotic xinmaining were composed with Moschus, Calculus Bovis, Borneol, Radix Ligusticum, Flos Sophorae Immaturus, Radix Salviae Miltiorrhizae, Leech, etc. This preparation was suitable for treating channels and collaterals type of cerebral thrombosis. The dosage was 2-4 capsules (0.5 g/capsule) oral administration twice per day, 3-4 weeks as a therapeutic course. The authors studied 158 cases of these patients compared with 117 cases of control group with dextran and Vinorutone. The clinical result showed that the obvious effective rate in the therapeutic group was 62.1% and the total effective rate 96.3%; the values in the control group were 38.5% and 86.3% respectively (P less than 0.01). The laboratory results showed that the blood viscosity, serum viscosity, hematocrit (vol %), RBC electrophoresis rate (micron/sec/v/cm) and platelet aggregation rate (%) before antithrombotic xinmaining administration were 5.82 +/- 0.82, 1.82 +/- 0.02, 52.81 +/- 6.70, 0.82 +/- 0.19 and 28.33 +/- 12.02 respectively; and those after the treatment were 4.72 +/- 0.65, 1.70 +/- 0.02, 48.76 +/- 0.40, 0.97 +/- 0.17 and 23.05 +/- 10.01 (mean +/- S), P less than 0.01. The toxicological study proved that the preparation was safe, no significant side-effect and good for cerebral thrombosis medication.

Adult↗
PubMed1991

[Differentiation of the sex of Trichinella larvae collected in Changchun].

The length of the rectum in male Trichinella spiralis larvae is about twice that in female larvae, being 54.39 (50.4-63.0) microns in males and 28.05 (18.9-31.35) microns in females. The gonad rudiment of the female larvae has already differentiated obviously into seminal receptacle rudiment and uterus rudiment, while that of the male larvae remains undifferentiated. The seminal receptacle rudiment is a granular, small mass and dark brown in color, while the uterus rudiment is composed of a column of several cells, and the total length of these two rudiments is 62.18 (50.4-75.6) microns. Verifications through experimental infections proved that the length of rectum and the degree of differentiation of gonad rudiment might be used as indices to identify the sex of larvae. It was found that the sexual ratio of T. spiralis collected in Changchun was 1.82:1 (1.17-2.59:1).

Animals↗
PubMed1991

The role of Se in the interconversion of polymeric states of spectrin from human erythrocytes.

It has been shown that Se can markedly prevent the dissociation of spectrin from erythrocyte ghosts. We now report that the transformation of incubated spectrin oligomers to its tetramers and dimers was obviously decreased in the presence of trace amounts (0.5-2.0 p.p.m.) of Na2SeO3. The spectrin tetramers and dimers are in a reversible equilibrium and Se could alter this equilibrium in favour of tetramers. This Se effect is concentration dependent and an inverse result was obtained with higher Na2SeO3 concentrations (greater than 4.0 p.p.m.). We suggest that the equilibrium state of the spectrin tetramer-dimer may be governed by a conformation adjustment induced by Se and the difference in conformation in the presence of low and high Na2SeO3 concentration may lead to an alteration of the spectrin tetramer-dimer balance.

Biopolymers↗
PubMed1990

Circadian rhythm of glucocorticoid receptors in human peripheral leukocytes and their reactivity to glucocorticoids.

1) There exists a CR of GR in human leukocytes, PMN, and monocytes with the peak values from 0400 to 0800 hr and the trough values between 2300 and 0000 hr. The difference between them was significant statistically. 2) The FI of the chemotactic migration rate of PMN by cortisol also showed diurnal changes which were synchronous with that of GR. This indicates that the CR of GR may be of functional significance. 3) In Cushing's syndrome, the CR of GR was normal in spite of the fact that the CR of plasma cortisol was disturbed. This indicates the independency of the CR of GR from that of cortisol. 4) In apoplexy caused by brain ischemia, the CR of GR was abolished in patients with basal lesions but preserved when the lesions were located in the cerebral cortex. These results strongly suggest that the main "circadian pacemaker" of GR is located in the basal brain, most probably in the suprachiasmatic nuclei as has been suggested for rodents.

Adult↗
PubMed1990

Morphometric study of neuromuscular junction in rabbits subjected to shock by superior mesenteric artery occlusion.

The purpose of this study was to describe changes in the neuromuscular junction of rabbit sartorius muscle after shock by superior mesenteric artery occlusion in 18 rabbits. The results revealed that the numeric and volume densities of the acetylcholine (Ach) vesicles of the sartorius neuromuscular junction were decreased during shock when compared by electron microscopy with normal subjects (p less than .001). We also discovered that the release of lysosomes from hepatic cells, erythrocyte acetylcholinesterase (AchE) activity, and hepatic ATP values decreased during shock. Both scopolamine (0.023 mg/kg) and verapamil (0.74 mg/kg) blocked the release of Ach vesicles and lysosomes, and increased hepatic ATP values. Scopolamine also increased AchE activity. This study shows that the parasympathetic activation plays an important role in mesenteric artery occlusion shock.

Acetylcholinesterase↗
PubMed1990

[The inhibitory effect of hydrocortisone on the chemotactic migration of human leukocytes].

Random migration (RM) and chemotactic migration (ChtM) of human leukocytes to yeast activated serum were studied with the modified Boyden chamber method. Both RM and ChtM showed circadian rhythm. Leukocytes migrated most rapidly at night. The difference between the peak (0:00) and trough values (8:00) of RM and ChtM was significant statistically (P less than 0.01). ChtM was inhibited by hydrocortisone (F) of physiological concentration (10(-9)-10(-7) mol/L) which was dose-dependent and completely antagonized by the competitive antagonist, RU38486. The inhibitory effect was much more evident with higher dose (more than 10(-5) mol/L) and it was also reversed by RU38486, but only partially. It is suggested that glucocorticoids (GC) may be a physiological regulator of the activity of leukocytes and its inhibitory action on ChtM may be involved in antiinflammatory mechanisms of GC of pharmacological doses. The action of physiological and pharmacological concentration of GC may be mediated by low affinity specific binding sites of glucocorticoid receptors.

Cell Migration Inhibition↗
PubMed1989

[The clinical manifestations and endocrine changes of anorexia nervosa].

We analyzed the clinical manifestations and endocrine changes of 15 cases of anorexia nervosa. One male, aged 42, and 14 females, aged 14-26 were involved in the study. The precipitating causes were chronic psychiatric trauma (60%), strain (27%) and abnormal fear of being fat (13%). All showed clinical manifestations of hypometabolism and malnutrition. Body weight decreased by 36.3 +/- 11.6% on average and 93% of the patients had lost more than 20% of their original weight. All women patients over 16 years old had amenorrhea. The daily intake of grain was less than 150 gm and had decreased by more than 67% as compared with earlier intakes. Although the patients were very thin, 3/4 could maintain ordinary indoor activities. The patients with anorexia nervosa had obvious endocrine disturbances, such as low serum FSH, LH and Ts levels and high basal serum GH and midnight serum cortisol concentrations. The response of TSH to TRH and of FSH and LH to LHRH were delayed, but serum GH and PRL levels rose normally after stimulation. All of these changes are secondary to severe body weight loss or hypofunction of the hypothalamus.

Adolescent↗
PubMed1989

[Changes in peripheral leukocytic glucocorticoid receptor in patients with ischemic and hemorrhagic stroke].

The maximal binding capacity (Ro) and dissociation constant (Kd) of glucocorticoid receptor (GCR) in peripheral leukocytes were estimated by radioligand binding method and the plasma cortisol levels measured in 25 stroke patients (hemorrhagic 15, ischemic 10), compared with 12 healthy controls, the plasma cortisol level in stroke patients were significantly higher. The plasma cortisol level of 15 hemorrhagic and 10 ischemic stroke patients and 12 controls determined by RIA were 1.12 +/- 0.21, 0.90 +/- 0.28 and 0.45 +/- 0.09 nmol/L respectively. Ro of leukocytic GCR in hemorrhagic stroke were significantly lower than that of ischemic stroke and controls. No difference was found between ischemic stroke and controls. No difference was found between ischemic stroke and controls. Ro of GCR in 15 hemorrhagic stroke, 10 ischemic stroke patients and 12 controls were 3496 +/- 424, 5678 +/- 1101 and 5940 +/- 763 sites/cell respectively kd of GCR were 10.47 +/- 4.17, 7.01 +/- 3.24 and 5.81 +/- 1.05 nmol/L respectively. Affinity of GCR in 15 hemorrhagic stroke patients was significantly lower. In conclusion, lower number and affinity of leukocytic GCR and higher plasma cortisol level were demonstrated in hemorrhagic stroke patients, but normal number and affinity of GCR and higher plasma cortisol level in ischemic stroke patients.

Adult↗
PubMed1989

[Comparative study of the ECG exercise test and ambulatory ECG monitoring after recovery from acute myocardial infarction].

Early ECG exercise tests (EET) and ambulatory ECG monitoring (AEM) were performed in 42 patients surviving AMI in order to determine the sensitivity of the two methods for detecting ST-segment deviation and arrhythmias. 23 patients had ST changes during EET and AEM. Of them, 21 patients had ST changes induced by EET and 10 were recorded by AEM. The more the ECG leads used for monitoring during and after EET, the higher the percentage of patients with ST changes will be. There were 2 cases with ST changes found in AEM only. All the 6 patients who had ST elevations during EET had an anterior infarction and echocardiograms did show that they had left ventricular aneurysms or abnormal ventricular wall movement. AEM recorded ventricular premature beats (VPBs) in 37 cases (88.0%), while EET induced VPBs in 8 patients. The 42 patients were followed up for an average time of 6 +/- 1.7 m. (3.4 to 9.3 m.) Cardiac death occurred in 2 cases. One of them had horizontal ST depression of 3 mm during EET, the other had a negative EET but multifocal VPBs during AEM. It is concluded that for detecting ST changes EET is more sensitive than AEM, while VPBs are more frequently found in AEM than in EET. The authors are of the opinion that for better, prediction of the prognosis of patients after AMI, it is preferable to have early EET in combination with AEM.

Aged↗
PubMed1987

[Preliminary study on the nucleic acid hybridization technic in detecting HSV-2 DNA corresponding sequence of cancer tissues of the uterine cervix].

In this paper, 34 samples, 25 from 18 cervical carcinoma patients and 9 from 8 non-cervical carcinoma patients, were assayed using (alpha-32P) dCTP HSV-2 DNA probe and nucleic acid hybridization technic. It was shown that the positive rates of HSV-2 DNA corresponding sequence were 50% (2/4), 36% (5/14) and 12% (1/8) in the in situ cancer, invasive cancer and non-cervical cancer tissues. No HSV was isolated from 7 cancer specimens which showed a positive reaction by nucleic acid hybridization.

Animals↗