Search PubMed⌕ Search

Biomedical subjects

Z Liu

Publications and source records attributed to Z Liu.

At least 1,315 records · Page 73Linked to original sources
PubMed1992

[Experimental study on the mechanism of free radical in blast trauma induced hearing loss].

The MDA content in the cochlear tissue and ABR hearing threshold were measured at different times after the explosion of the guinea pigs. Results showed that there were two high peak values. The MDA increases at one hour after explosion; at 3 and 6 days it was significantly increased (first peak); at 8 days it reduced to normal level; at 12 days it again remarkably increased (second peak). It was in accordance with ABR hearing threshold changes. This suggests that increasing oxygen free radical reaction may be one of the causes of damage in blast trauma induced hearing loss.

Animals↗
PubMed1992

Use of computerized interactive morphometry in the diagnosis of mammary adenoma and adenocarcinoma in dogs.

We attempted to define quantitative objective criteria for diagnosis of mammary adenoma and adenocarcinoma in dogs. To that end, correlation between diagnosis made by conventional histologic examination and morphometric descriptors, obtained by computerized histologic analysis, was assessed in biopsy specimens of mammary tissue from 63 dogs. We used 2 interactive computer procedures: one assessed mean nuclear perimeter, mean nuclear area, and circularity factor; and the other evaluated nuclear stratification and cell crowding. A data base was generated with 11 specimens from normal mammary tissue, 17 specimens from mammary adenoma, 18 specimens from low-grade mammary adenocarcinoma, and 15 specimens from mammary adenocarcinoma. The mean values of nuclear perimeter, nuclear area, nuclei per millimeter of basement membrane, and minimal distances from cells to basement membrane gradually increased from normal to high-grade malignancy. Distributions of nuclear areas and of minimal distances from cells to basement membrane were shifted in specimens from malignant tumors. Multivariate analysis confirmed the homogeneity of the diagnostic groups.

Adenocarcinoma↗
PubMed1992

Prophylactic and therapeutic effects of acupuncture on simple obesity complicated by cardiovascular diseases.

In order to understand the prophylactic-therapeutic effects of acupuncture and moxibustion in simple obesity complicated by cardiovascular diseases, we have observed in 102 cases the changes of pathogenetic and hazardous factors and the regulating function of vegetative nerves on cardiovascular activities. The results showed that the therapeutic effect of acupuncture and moxibustion was good with a total effective rate of 88.24%. At the same time, acupuncture and moxibustion were found to have a benign conversion effect on the loin hip ratio (the pathogenetic factor), the arteriosclerotic index (the hazardous factor), and the vegetative nerve function of regulating the heart and blood vessels (the equilibrium indices of the vegetative nervous system). All this suggests that acupuncture is a treatment of choice for obesity and an important method of preventing and treating complicating cardiovascular diseases.

Acupuncture Therapy↗
PubMed1992

[Tissue-specific expression of the chimeric gene delta KpF in transgenic mice].

The expression of the chimeric gene delta KpF in which the promoter region of delta-crystallin gene was replaced with the long terminal repeats (LTR) of Friend spleen focus forming virus (SFFV) was studied in transgenic mice for approaching the regulatory mechanism of the expression of chicken delta-crystallin gene. The recombinant plasmid (p delta KpF) DNA containing delta KpF gene was microinjected into male pronuclei of fertilized mouse eggs. The injected eggs were implanted into the oviducts of pseudopregnant female mice and allowed to develop to term. Subsequently, 35 mice from those eggs were born. The mice were analyzed at 2 weeks of age with respect to gene integration and expression by the method of DNA blot hybridization and immunoenzymologic assay. DNA-DNA hybridization indicated that the genomic DNA from one of the mice retained the sequences that hybridized strongly with the probe, p delta KpF. Enzyme linked immunosorbent assay (ELISA) showed that delta KpF gene was expressed in the lens, but not in the brain, muscle and liver. These results demonstrate that the essential regulatory elements for tissue-specific expression of chicken delta-crystallin gene reside in the sequences downstream from +677bp.

Animals↗
PubMed1992

[Construction and identification of vectors containing maize plasmid-like DNA S1 and reporter genes].

The reporter Gene GUS with CaMV 35S promoter was inserted into plasmid pBS[1] in reversal direction of integration, and two kinds of recombinant plasmids were obtained. These results were verified by restriction endonuclease analysis and southern hybridization. A piece of 10.8kb fragment containing NPT II reporter gene from digested pBI121.1 by BamHI and EcoRI was ligated together with 3.9 kb fragment of plasmid-like DNA S1. Then generate a recombinant plasmid pBIS5 was generated. These three vectors can be used to transform maize protoplasts. High frequency of transformation may be expected due to homology between plasmid-like DNA S1 and maize nuclear DNA.

DNA↗
PubMed1991

Intrathalamic injections of gamma-hydroxybutyric acid increase genetic absence seizures in rats.

The effects of intrathalamic injections of gamma-hydroxybutyric acid (GHB) and of NCS 382 85, a specific antagonist of GHB receptors, were evaluated in rats with spontaneous generalized absence epilepsy. Bilateral injections of GHB (25 and 50 micrograms/side) into the mediolateral thalamus increased spontaneous spike and wave discharges (SWD) in a dose-dependent fashion. This effect was suppressed by administration of NCS 382 85 (50 micrograms/side). Bilateral injection of NCS 382 85 alone (50 and 100 micrograms/side) into the same sites had no effect on SWD duration. Injection of GHB or NCS 382 85 into the midline thalamus and the area of reticular nuclei did not modify the SWD. These data suggest that GHB receptors in the mediolateral thalamus may be involved in the control of spontaneous SWD in this rat model of petit mal epilepsy.

Animals↗
PubMed1991

Evidence for a critical role of GABAergic transmission within the thalamus in the genesis and control of absence seizures in the rat.

The involvement of GABAergic transmission within the thalamus in the generation and control of spike and wave discharges (SWD) in generalized non-convulsive or absence epilepsy was studied in rats with spontaneous SWD and in non-epileptic rats. In epileptic rats, bilateral injections of gamma-vinyl GABA (GVG, 10 micrograms/side) or muscimol (10 ng/side) into the medial part of the ventral lateral thalamus, i.e. the specific relay nuclei, significantly increased spontaneous cortical SWD whereas similar injections into the most lateral part of the thalamus, i.e. the area of the reticular nuclei, significantly suppressed these seizures. Injections of GVG (20 micrograms) or muscimol (20 ng) into the midline thalamus had no direct effect on the spontaneous SWD. In non-epileptic rats, injections of GVG (25 micrograms/side) or muscimol (100 ng/side) into the thalamic relay nuclei produced short SWD on the cortical EEG. These results suggest that GABAergic neurons in the reticular nuclei and their projections to the specific relay nuclei of the thalamus are involved in the elicitation and control of generalized non-convulsive seizures.

Aminocaproates↗
PubMed1991

The effect of contextual variety on the practice, retention, and transfer of an applied motor skill.

Laboratory research in motor learning has consistently demonstrated higher retention and/or transfer when practice occurs under conditions of high contextual variety (e.g., Lee & Magill, 1983; Newell & Shapiro, 1976; Shea & Morgan, 1979;). In the present study, an attempt was made to determine whether a contextual variety effect could be demonstrated in a standard physical education instructional setting. During practice trials on the long and short badminton serves, male and female subjects performed under either blocked (i.e., all trials of one serve followed by all trials of the other) or varied (i.e., alternating trials of long and short serves) conditions. Retention and transfer tests (i.e., using the service area opposite that employed during the practice phase) were administered at the end of the badminton unit. Although little difference was observed in the performance of the two groups during practice, alternating-trial subjects demonstrated significantly higher retention of the short serve and significantly higher transfer of both serves than blocked-trial subjects. The performance of male and female subjects was not differentially influenced by practice structure conditions. It was concluded that a practice schedule that requires performers to change their plan of action from trial to trial may facilitate the retention and transfer of motor skills in applied instructional settings.

Adult↗
PubMed1991

Regional changes in hemodynamics and cardiac myocyte size in rats with aortocaval fistulas. 1. Developing and established hypertrophy.

The effects of a large arteriovenous fistula on left and right ventricular hemodynamics and cardiac myocyte size were examined in adult rats at 1 week and 1 month after surgery. Cardiac output, left ventricular function, and right ventricular function were evaluated before obtaining isolated myocytes for cell size measurements. Average heart weight increased 35% at 1 week and 86% at 1 month in rats with fistulas. In general, myocyte hypertrophy was due to a proportional increase in length and width (length/width ratio remained constant). This change was more evident in the large hearts from rats with 1-month fistulas. At both the 1-week and 1-month intervals, the hypertrophic response of right ventricular myocytes was slightly greater than that observed in the left ventricle or interventricular septum. Left ventricular systolic pressure and dP/dtmax were significantly reduced at 1 week but returned to normal after 1 month of overloading. Left ventricular end-diastolic pressure was increased approximately fivefold and twofold at 1 week and 1 month, respectively. Right ventricular systolic pressure and dP/dtmax were increased at both intervals examined. We conclude that severe volume overloading from a large aortocaval fistula in the rat is characterized by 1) depressed left ventricular function at 1 week followed by a large compensatory hypertrophy and near normal function at 1 month, 2) right ventricular pressure overload, and 3) changes in myocyte shape that resemble normal physiological growth.

Animals↗
PubMed1991

Regional changes in hemodynamics and cardiac myocyte size in rats with aortocaval fistulas. 2. Long-term effects.

Regional changes in hemodynamics and cardiac myocyte size were examined in adult rats 5 months after creating a large aortocaval fistula. At that time, cardiac output, left and right ventricular pressures, and left and right ventricular dP/dtmax were measured. Subsequently, isolated cardiac myocytes were collected from the left ventricle, right ventricle, and septum for cell size measurements. Compared with sham-operated controls, percent dry weight was reduced in the liver and kidney but was unchanged in the lung. Heart rate, left ventricular systolic pressure, left ventricular dP/dtmax, and systolic aortic pressure were not changed in rats with fistulas. However, cardiac output, stroke volume, left ventricular end-diastolic pressure, and all measured parameters in the right ventricle were significantly increased. Mean cell volume and the ratio of heart weight to body weight were both elevated 92%. Cell volume, cell length, and cross-sectional area increased significantly in each heart region examined. Hypertrophy was more pronounced in cells from the right ventricle and the endomyocardium of the left ventricle. The percentage of cells with mononucleation or binucleation was not changed in any heart region of rats with fistulas. In summary, despite evidence of renal and hepatic congestion, most indexes of cardiac function were normal or elevated 5 months after creation of a large volume-overload-induced hypertrophy. Data from isolated cardiac myocytes suggested that cellular hypertrophy, rather than hyperplasia, was responsible for the increased cardiac mass.

Animals↗
PubMed1991

Anterior tarsal tunnel syndrome.

We have reviewed 10 patients treated for anterior tarsal tunnel syndrome produced by compression of the deep peroneal nerve or its branches, and we have studied the anatomy of the tunnel in 25 adult feet. The causes of onset of the syndrome included contusion of the dorsum of the foot, tight shoe laces, talonavicular osteophytosis, ganglion, and pes cavus. The clinical signs were often diagnostic but electromyography was helpful. Operative decompression in nine feet of eight patients gave successful results at 1.5 to 4 years follow-up.

Adolescent↗
PubMed1991

Changes of glomerular fixed anionic charge sites in adriamycin nephrosis in rats.

A single intravenous injection of adriamycin (5 mg/kg) into rats induced nephrotic syndrome. In the various stages of the model, alterations of glomerular fixed anionic charge sites stained with colloidal iron were analyzed quantitatively by image analyzer, which is reported here for the first time. The results showed that there was a significant decrease in glomerular fixed anionic charge sites at 3 hours after administration of adriamycin as compared with the control animals (P less than 0.01). Marked loss of the anionic charge sites preceded the onset of proteinuria and steadily increased along with the progress of the disease. The results suggest that the loss of glomerular fixed anionic charge sites may play an important role in the development of proteinuria in nephrotic syndrome.

Animals↗
PubMed1991

[Effect of intracerebral injection of substance P on serotonin contents of several brain regions and its relation with pain threshold, electroacupuncture analgesia in rats].

The purpose of this study is to observe the effect of intracerebroventricular (icv) and intra-PAG injection of substance P (SP) on serotonin (5-HT) contents of hypothalamus, hippocampus, striatum and its relation with the change of pain threshold, electroacupuncture (EA) analgesia. The results were as follows: (1) After icv injection of SP, the pain threshold and the 5-HT contents of hypothalamus, hippocampus were significantly increased. After depletion of the 5-HT contents in brain by pCPA, the inhibitor of 5-HT synthesis, the effect of SP on elevating pain threshold and the 5-HT contents of hypothalamus, hippocampus were markedly attenuated, bud did not prevent the analgesic effect of SP (2) The pain threshold and the 5-HT contents of hypothalamus, hippocampus were dose-dependently increased by intra-PAG injection of SP. (3) The intra-PAG injection of SP introduced simultaneously with high or low frequency EA did not affect the change of 5-HT contents of three brain regions, but caused a more marked elevation of pain threshold. These results suggest that the serotoninergic system may be activated by PAG for the mediation of SP induced analgesia. There is a synergic action of analgesia between the effects produced by intra-PAG injection of SP and those by high or low frequency EA.

Acupuncture Analgesia↗
PubMed1991

[The relationship between hepatitis B and renin-angiotensin-aldosterone system].

The angiotensin II (AT II) levels in plasma were measured 68 times by using radio-immunoassay in 30 patients with viral hepatitis B (HB) and in 35 healthy persons as the control group. The results showed that the AT II levels of patients with HB were much higher than those of the control group (P less than 0.001). They were 219.25 +/- 91.31 ng/L and 60.70 +/- 10.73 ng/L, respectively. These indicated that the renin-angiotensin-aldosterone system (RAAS) of the patients was in exciting state. The levels of 8 cases of severe chronic active hepatitis (SCAH) (AT II = 270.40 +/- 106.55 ng/L, 6 cases of subacute fulminant hepatitis (SFH) (AT II = 332.80 +/- 140.12 ng/L), and 4 cases of hepatocirrhosis (HC) (AT II = 218.50 +/- 97.64 pg/ml) were all higher than those of 8 cases of chronic active hepatitis (CAH) (100.50 +/- 83.81 ng/L) and those of 4 cases of acute icteric hepatitis (A1H) (123.33 +/- 64.97 ng/L). These findings showed that the levels of AT II were directly related with the severity of the illness. The AT II levels of 8 cases of HRS (270.50 +/- 66.31 ng/L) were higher that those without HRS (174.50 +/- 78.48 ng/L). After treatment with captopril (CPT), the renal function of the patients returned to normal and the patients got better, while the AT II levels decreased greatly. The results suggested that high AT II levels in plasma may be one of the causes aggressing the HRS. The CPT may inhibit the produce of AT II and there are some therapeutic effects for the HRS.

Adult↗