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Biomedical subjects

Z Liang

Publications and source records attributed to Z Liang.

At least 163 records · Page 9Linked to original sources
PubMed1992

Simultaneous compensation for attenuation, scatter and detector response for SPECT reconstruction in three dimensions.

A three-dimensional reconstruction method for simultaneous compensation of attenuation, scatter and distance-dependent detector response for single photon emission computed tomography is described and tested by experimental studies. The method determines the attenuation factors recursively along each projection ray starting at the intersected source voxel closest to the detector. The method substracts the scatter energy window data from the primary energy window data for scatter compensation. The detector response is modelled to be spatially invariant at a constant distance from the detector. The method convolves source distribution with the modelled response function to compensate for the smoothed by use of a non-uniform entropy prior to searching for the maximum a posteriori probability solution. The method was tested using projections acquired from a chest phantom by a three-headed detector system with parallel hole collimators. An improvement was shown in image noise, recognition of object sizes and shapes, and quantification of concentration ratios.

Image Processing, Computer-Assisted↗
PubMed1992

The status quo, regional differences, and trend of the Chinese family structure.

"Based on the 10% machine aggregate data of the fourth census of 1990 and the 1% computer sampling data, this article attempts to analyze the status quo and regional differences of China's family structure and their relationships with the level of social and economic development, and the trend of the Chinese family structure since the 1980s."

Asia↗
PubMed1992

[The effect of acupuncture on rabbits with fever caused by endotoxin].

Forty-eight rabbits were used to investigate the effect of puncturing GV14, LI11 on the change of temperature and the level of plasma endotoxin. The animals were divided into 5 groups: reinforcing manipulation, reducing manipulation, electroacupuncture, endotoxin-control, N.S.-control group. The result shows that there is no influence on the fever caused by endotoxin and the level of plasma endotoxin in the treatments by the different acupuncture techniques.

Acupuncture Therapy↗
PubMed1992

[The influence of different acupuncture manipulations on the plethysmogram of the patient with kidney deficiency].

In order to prove the specific property between the tonifying manipulation (TM) and reducing manipulation (RM), and search further for the key in improving the effect of manipulation, the influence of to on two different manipulations. The plethysmogram in the same body-condition (kidney-deficiency) One was TM with slow-trusting and quick lefting; the other was RM with the converse movement. Randomized block design, cross-over design and single-blind design were used. The result showed that the TM increased the amplitude of the plethysmogram obviously, whereas the RM had no significant influence on it. There was significant difference not only between the TM group and the central group, but also between the TM group and RM group (P less than 0.01 or P less than 0.05). The difference between the RM group and the control group was not significant (P greater than 0.05). Meanwhile, it was recommended that "mind concentration" on acupuncture manipulation is important. In conclusion, the experiment demonstrated the experimental evidence for explaining the mechanism of TM and RM. It was suggested that acupuncture manipulations are worthy to pay attention so as to improve clinical effect.

Acupuncture Therapy↗
PubMed1991

Laser-excited atomic fluorescence in a flame as a high-sensitivity detector for organomanganese and organotin compounds following separation by high-performance liquid chromatography.

The coupling of a high-performance liquid chromatograph with a sensitive and selective laser-excited atomic fluorescence spectrometry (LEAFS) detector is described. In connection with this, a study of the signal and noise characteristics of instrumentation for dispersive, nondispersive, and front surface LEAFS is reported together with a comparison of the sensitivity and selectivity achieved with high-performance liquid chromatography (HPLC)-flame LEAFS, HPLC-ultraviolet (UV), and HPLC-continuum source excited flame atomic fluorescence spectrometry (AFC) instrumentation. The HPLC-flame LEAFS instrumentation was applied to an investigation of the Mn species responsible for (methylcyclopentadienyl)manganese tricarbonyl (MMT) toxicity in rats. The detection limits for various organomanganese species by HPLC-flame LEAFS ranged from 8 to 22 pg of manganese. Recovery of these compounds from rat urine varied between 80% and 100%, with a reproducibility of between 4% and 8% relative standard deviation. Preliminary data for the HPLC-flame LEAFS determination of toxic alkyltin compounds are reported.

Chromatography, High Pressure Liquid↗
PubMed1991

Pulse timing and optical interface between a neodymium: yttrium aluminum garnet laser and a Fourier transform ion cyclotron resonance mass spectrometer.

Laser desorption/ionization combined with pulsed (time-of-flight or Fourier transform ion cyclotron resonance) mass spectrometric detection is a powerful technique for analysis of involatile compounds and mixtures. Such experiments were originally conducted with pulsed CO2 lasers. Although a pulsed CO2 laser can be operated in single-shot mode, Nd: YAG lasers perform best with multiple flashes for warm-up before the final Q-switch output light pulse, thus creating the need to synchronize the desired final laser-output pulse with the event sequence for mass spectrometric analysis. In this paper, we describe a new and simple interface (both optical and electronic components) between a Continuum (formerly Quantel) Model YG 660A Nd:YAG laser and an Extrel FTMS-2000 mass spectrometer. The optics are modified from a prior pulsed CO2 laser interface from Extrel. Synchronization between the Nd:YAG laser and the mass spectrometer event sequence is achieved by means of a simple timing circuit that uses an inexpensive pulsing device and is triggered by pulses generated directly from the Extrel 1280 data system and cell controller, in contrast to the only prior published method that required an auxiliary microcomputer. The present interface method is highly flexible, and makes possible complex sequence events involving laser pulses for e.g.: desorption/ionization of solids; photoionization of gaseous neutrals; and photodissociation and photodetachment of gaseous ions.

Lasers↗
PubMed1991

[Preliminary study of cervicovaginal peroxidase as indicator for ovulation].

The study was designed to determine whether the change in the pattern of cervicovaginal peroxidase activity in the fertile period of women can serve as a basis for the development of a technique to predict ovulation time in natural family planning. Eight healthy women volunteered for this study in Chengdu area. The samples of cervical mucus and vaginal secretion were collected. The specific G-Px activity was measured with reference to the procedure of Tsibris, et al., on days 6, 8, 10, 12 through 16, 18, 20, 22, 24 of each menstrual cycle; at the same time an antecubital venous blood sample was drawn to be analyzed for levels of LH, FSH, E2, and P by RIA. The data showed that in 7 ovulatory cycles the G-Px activity did not vary regularly in vaginal secretion but it did drop rapidly in cervical mucus 2 or 3 days before ovulation time and it rose again one day after ovulation. The results suggest that the measurement of the G-Px activity in cervical mucus can be used to predict ovulation by two to three days before the time.

Cervix Mucus↗
PubMed1991

[Evaluation of a logistic regression model in predicting the prognosis of Graves' disease treated by antithyroid drugs].

One hundred and twelve new cases of Graves' disease were treated by tapazole for 6 months and followed up for another 12 months. The initial dose was 30 mg/d. Clinical and biochemical euthyroidism was achieved within 1 to 3 months, then a maintenance was given until cessation of drugs at 6 months. One hundred and eleven cases completed the study. Remission and relapse were defined at the end of follow-up for 1 year according to the presence or absence of clinical manifestation of hyperthyroidism and the levels of T3 and T4. The results of the 12-month follow-up showed that 46 of 111 cases were in remission, and the remaining 65 cases suffered relapse. A logistic regression model with 4 variables was established, which included thyroid suppression rate and goitre size by palpation at the end of drug treatment, the level of T3 before therapy, and the patients' age. The model had 81.5% sensitivity, 84.8% specificity and 82.9% (92/111) accuracy in predicting the outcome of Graves' disease after withdrawal of drug for 1 year. The results were much better than any other univariate analysis in this study.

Adolescent↗
PubMed1991

[Intrauterine adhesion and ovulatory disorder following induced abortion].

Follicular stimulating hormone, luteinizing hormone, prolactin, estradiol and progesterone were measured by radioimmunoassay in 34 patients with those from 34 normal cycling women after induced abortion. The result showed that the anovulatory incidence of the patients (20.6%) was significantly higher than that of the controls (2.8%) (P less than 0.05). Increased prolactin and premature ovarian failure might be responsible for the anovulatory disorder, resulting in unsatisfactory restoration of fertility. It is suggested that the low success rate in treating patients with intrauterine adhesion after induced abortion may be due to premature ovarian failure and hyperprolactinaemia.

Abortion, Induced↗
PubMed1991

[Further study on the treatment of severe beta-thalassemia with myleran].

In a previous paper we reported the results of treatment of five patients with beta-thalassemia major with myleran. Three more cases are reported in this paper. After 40-50 days of oral administration of myleran, major hematological findings (Hb, HbF, RBC) began to increase and remained at higher level for 4-5 months before dropping back to the original. The results of analysis of sister chromatid exchange (SCE) showed no irreversible damage on chromosomal DNA of the patients at the dosage used (0.2 mg/kg.d). It was also demonstrated that the effect of treatment does not seem to be related to the types of beta-globin gene mutations of the patients.

Busulfan↗
PubMed1990

[Observation of the outcome of 112 cases with Graves' disease treated by short-term antithyroid drug therapy for one year].

One hundred and twelve new cases with Graves' disease were treated by tapazole for 6 months and followed-up for another 12 months in a prospective study. One hundred and eleven cases completed the whole course of study, and only one failed to be followed up. The results of the follow-up for 12 mon showed that the remission rate was 41.4% (46/111) and relapse rate was 58.6% (65/111). The present study indicated that the remission or relapse was related with serum levels of T3 before treatment, shrank goiter and disappearance of goiter bruit during the treatment as well as thyroid suppression rate, but not related to sex, age, period of illness before therapy or severity of the disease. It is suggested that a 6-mon antithyroid drug therapy instead of traditional long term therapy may be suitable for those patients who are with a reduced goiter and disappeared goiter bruit during the antithyroid therapy, and suppressible thyroid up-take by T3 and whose serum levels of T3 before treatment are not very high. So the patients may benefit from the short-term therapy. They are not only able to obtain a prolonged remission but also save time and money.

Adolescent↗
PubMed1989

Establishment of Panax notoginseng tissue culture.

Calli were induced from Panax notoginseng roots, tubers, stems, petioles, leaves, and flower buds, and preliminary identification of medicinal compounds in the callus was carried out by TLC, using subcultured sixth-generation calli. The results demonstrated that callus was capable of synthesizing saponins, including ginsenosides Rb1, Rg1, and Rh1. The saponin content (5.33%, D.W.) in the callus was higher than that in intact plants (4.25%, D.W.). Callus also produced a larger amount of sapogenins than intact plants. Callus growth rate was 54.0 mg D.W./liter/day. Callus induced from stems was superior in terms of growth, saponin and sapogenin contents, and saponin composition. MS medium proved optimal for growth of callus induced from stems. The optimum pH was about 5.8 and the optimum temperature about 26 degrees C. Light had little stimulatory effect on callus growth.

Chromatography, Thin Layer↗