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Biomedical subjects

D Li

Publications and source records attributed to D Li.

At least 883 records · Page 49Linked to original sources
PubMed1991

[Disposition of 3-(N-piperidinomethylarino)methyl-rifamycin SV (FCE 22250) in rats].

After rats being given ig FCE 22250 5, 10 and 25 mg.kg-1, the plasma peak times (Tmax) were 12-14 h, the max plasma concentrations (Cmax) were 3.0, 5.6 and 12 micrograms.ml-1 respectively, and the half-lives of elimination (T1/2) were 24-26 h. The apparent volumes of distribution of the three doses were about 1 L.kg-1, suggesting that FCE 22250 in blood and in tissue was balanced. Total body clearance rate of each of the three doses was 29 ml.kg-1.h-1. The ig absolute bioavailability ranged from 69-84%. Its distribution in rats was as follows: the highest in liver, next in lung and then in fat, kidney, intestine, spleen, lymphaticode, heart, muscle, testis, the lowest in brain. It was eliminated mainly via the bile with feces. The human serum protein binding rate of FCE 22250 was 96.2%. It was shown that the rate was not correlated with drug concentration in serum under our experimental conditions.

Animals↗
PubMed1990

Role of heme in phenobarbital induction of cytochromes P450 and 5-aminolevulinate synthase in cultured rat hepatocytes maintained on an extracellular matrix.

When hepatocytes are cultured on matrigel, a reconstituted basement membrane matrix, mRNAs for cytochrome P450 class IIB1/2 and class III genes can be induced by treatment with phenobarbital. We took advantage of this new system to critically evaluate the role of heme as a regulator of these cytochromes P450 and of 5-aminolevulinate synthase (ALA-S), the rate-limiting enzyme in heme biosynthesis. Phenobarbital treatment of rat cultures increased the total amount of cytochrome P450, activities catalyzed by IIB1/2 (benzyloxy- and pentoxyresorufin O-dealkylases) and ALA-S activity, and ALA-S mRNA. Treatments with phenobarbital combined with succinyl acetone, an inhibitor of heme biosynthesis at the step of 5-aminolevulinate dehydrase, blocked the induction of the proteins for cytochrome P450IIB1/2 and cytochrome P450IIIAI, as indicated by spectral, immunological, and enzymatic assays. However, at the same time, succinyl acetone cotreatment failed to inhibit the induction of the mRNAs for cytochrome P450IIB1/2 and cytochrome P450IIIA. Lack of effect on the cytochrome P450 mRNAs was selective inasmuch as treatment with phenobarbital combined with succinyl acetone synergistically increased both ALA-S activity and ALA-S mRNA, presumably by blocking formation of heme, the feedback repressor of ALA-S. Indeed, the increase in ALA-S mRNA caused by the combined treatment was abolished by adding heme itself to the cultures. In contrast to earlier concepts, we conclude that in the intact hepatocyte, phenobarbital-induced cytochrome P450 induction is independent of changes in heme synthesis.

5-Aminolevulinate Synthetase↗
PubMed1990

Role of pH in syncytium induction and genome uncoating of avian infectious bronchitis coronavirus (IBV).

Syncytium formation induced in Vero cells by IBV-Beaudette was optimal at pH 6.7 and absent at pH 7.5. Reduction of IBV-Beaudette replication by ammonium chloride, which raises the pH in endosomes, further indicated that uncoating of the virus genome probably occurred within the acidic environment of endosomes. However, this would not appear to apply to all IBV strains, since one was unaffected by the drug. It would appear that some strains of IBV have the capacity to fuse with the plasma membrane at neutral pH, thereby leading to genome uncoating at that site. Other strains of IBV might also uncoat at the plasma membrane when the extracellular environment is slightly less than pH7.

Ammonium Chloride↗
PubMed1990

Molecular basis of the variation exhibited by avian infectious bronchitis coronavirus (IBV).

IBV serotype-specific, virus neutralising (VN) antibody is induced by the S1 subunit of the spike (S) glycoprotein. A Portuguese isolate (Port/322/85) is considered to be an in vivo recombinant. VN tests showed that it belongs to the Massachussetts (Mass) serotype. Correspondingly, the sequence of S1 and S2 was extremely similar to that of older Mass isolates. However, the matrix (M) glycoprotein and upstream gene sequences were atypical of these Mass strains and more closely resembled other serotypes isolated in Europe. The recombination event had occurred within the sequence between the M and S genes (corresponding to mRNA 3) or near the 3' terminus of the S2 gene.

Amino Acid Sequence↗
PubMed1990

PET, CT, and MRI imaging of neuronal migration anomalies in epileptic patients.

During the investigation of intractable epilepsy, neuronal migration anomalies [NMA] were discovered in three patients. The first patient had abnormally positioned gray matter within the walls of both lateral ventricles. The second patient had a post operative cystic area in the right parietal-occipital lobes and an area of NMA within the right temporal lobe. The third patient had abnormally thickened gray matter in the right operculum. Long term CCTV-EEG monitoring of these three patients revealed ictal discharges originating from the area of abnormal gray matter in patients 2 and 3. PET scanning showed the areas of NMA in all three patients to have similar metabolic activity to normal gray matter. These cases illustrate the value of various imaging modalities and suggest some interesting physiology of a spectrum of neuronal migration anomalies.

Adolescent↗
PubMed1990

A seral epidemiological study of HIV transmitted through human seral gamma-globulin preparations.

In order to study the potential risk of transferring HIV through human seral gamma-globulin preparations (immunoglobulin), indirect immunofluorescent antibody test (IFA) and Western Blot (WB) assay were applied to 343 random samples (sera) with previous injection of imported human seral gamma-globulins (Ig) positive for Human Immunodeficiency Virus (HIV) antibodies between 1981-1987 for the detection of HIV antibodies. All results were negative and tests on all 23 controls who had previously received Ig made in China also gave negative results. However all 12 batches of imported Ig collected from the above-mentioned users, were positive for HIV antibodies when tested by WB and IFA. This study shows that under normal conditions, human seral gamma-globulin does not transmit HIV.

Adolescent↗
PubMed1990

An empirical model for analysing and interpreting ventricular measures.

Given the abundant and, at times, contradictory studies of ventricular enlargement in neurological and psychiatric disorders, the current study was carried out to provide an empirical basis for analysing and interpreting these measures. A sample of CT scans on 100 control subject was drawn from the files of the University of British Columbia Department of Radiology and 19 measures of ventricular and head diameter or area were made. The interrelationships of these measures were then examined using factor analytic procedures. Three ventricular dimensions were found. To validate these three dimensions, the relationship of each with age was examined and then the age-corrected scores of seven clinical groups were compared on each of these dimensions. The magnitude of the relationship between these dimensions and age was impressive and each dimension contributed unique information regarding these age-related changes. Moreover, the analysis of the clinical groups suggested that differential patterns of ventricular change were present dependent upon the disease. These results are discussed with a view to integrating the findings of previous studies and planning future studies.

Adult↗
PubMed1990

Daytime hypercapnia in the development of nocturnal hypoxemia in COPD.

Arterial oxyhemoglobin saturation (SaO2) falls to a variable extent during sleep in patients with COPD. These nocturnal falls in SaO2 may contribute to the development of pulmonary hypertension, nocturnal cardiac arrhythmias, and death during sleep. In order to determine which physiologic factors measured during wakefulness might contribute to the development of nocturnal hypoxemia, we performed multiple stepwise linear regression analyses in 48 patients with stable COPD with mean and lowest nocturnal SaO2 as dependent variables. It was concluded that the two chief variables, measured while awake, which are associated with alterations in nocturnal oxygenation in patients with COPD are baseline awake SaO2 and PaCO2. Hypercapnia appears to be a risk factor for the development of nocturnal hypoxemia in patients who are normoxic while awake.

Humans↗
PubMed1990

Report on Shanghai norms for the Chinese translation of the Wechsler Intelligence Scale for Children-Revised.

The Chinese translation of the Wechsler Intelligence Scale for Children--Revised (WISC-RC) was administered to 660 children (ages 6 through 16 yr.) in the city of Shanghai. The obtained norms represent children's intelligence levels in big cities where the economic and cultural development is advanced. The norms are reported as "Scaled Score Equivalents of Raw Scores" for each age group and as "IQ Equivalents of Sums of Scaled Scores." The reliability and validity of the norms indicate that the WISC-R is suitable for use with school-age children in China. The difference between the results for our Shanghai sample (WISC-RCs) and a USA sample (WISC-R) is also discussed.

Adolescent↗
PubMed1990

Ex vivo spermine dialdehyde treatment prevents lethal GVHD in a murine bone marrow transplantation model.

Spermine dialdehyde (SDA), an oxidized product of spermine which irreversibly suppresses T cell and NK cell activities, was evaluated as an ex vivo purging agent in the prevention of graft-versus-host disease (GVHD) in mice transplanted with SDA-treated allogeneic bone marrow. In this model, lethally irradiated C3H (H-2k) mice received BALB/c (H-2d) bone marrow and spleen cell mixtures which had been treated ex vivo for 10 min with SDA. Mice receiving SDA-treated cells survived past 100 days whereas mice in the control group died between days 25-35 suffering from severe GVHD. Surviving mice from the SDA-treated groups exhibited full chimerism at day 120. In vitro assays indicated that SDA inhibited T cell and NK cell activities at concentrations that spared myeloid cell growth. When a minimum number of bone marrow cells were used for reconstitution, SDA-treated marrow reconstituted lethally irradiated mice as effectively as control marrow suggesting that SDA had little impact on early myeloid cells which are required for engraftment. SDA may have clinical application as a purging agent in allogeneic bone marrow transplantation.

Animals↗
PubMed1990

[An acute experimental study on the combinations of aluminum and fluorine in various ratios].

The joint actions were assessed by four methods after male Wistar rats had been acutely intoxicated with nine proportional mixtures of Al and F. Strong antagonistic effects of Al on F were observed in the mixtures, in which the ratio of Al to F ranged from 0.8:0.2 to 0.1:0.9. The optimum ratio of Al to F for antagonism ranged from 0.3:0.7 to 0.1:0.9 without periorbital bleeding that was a regular finding in Al acute toxicity on the rat to be seen. When the amount of Al in the mixture was below 5% or above 90%, no antagonistic effect was shown. The kinetics on the absorption under the condition of Al and F existing simultaneously is still unknown, and warrants further investigation.

Aluminum↗
PubMed1990

[Use of calcium-channel blockers in cirrhotic patients with portal hypertension].

Four calcium-channel blockers (CCB)-nifedipine (NIF), verapamil (VER), cinnarizine (CIN) and tetrandrine (TET)-are currently available and widely used at home and abroad for the treatment of cardiovascular diseases. To confirm any effects of CCBs on cirrhotic patients with portal hypertension, the esophageal variceal pressure (EVP) during routine gastroscopy, hemodynamic study, portal venous pressure and rebleeding rate of esophageal varices after 18 months were measured and compared in 321 patients from 23 hospital. The results demonstrated that the CCBs could significantly reduce the EVP, portal venous pressure and the portal blood flow in cirrhotic patients with portal hypertension. Furthermore, we found that neither heart rates nor blood pressure showed any significant change in spite of pressures and flow reduction. The proportion of patients free of recurrent gastrointestinal bleeding 18 months after inclusion in this study was 87.9% in the TET group, which was much higher than in the other 4 groups (p less than 0.05). The results of this study suggest that TET seems to be more appropriate for cirrhotic patients with portal hypertension at the present time.

Adolescent↗
PubMed1990

[Primary study of iontophoresis of zinc ion in treatment of retinitis pigmentosa].

We report here the preliminary effects of zinc iontophoresis in treatment of 26 Rp patients who had decreased zinc serum level or abnormal ratio of serum copper to zinc. Through more than 20 to 30 times of therapy, the vision of 15.38% eyes increased more than "3 lines", 4% eyes increased more than 5 degrees in the visual field, 13.46% eyes improved in dark adaptation threshold (greater than 1.0), the visual functions of the rest eyes were slightly improved or unimproved. The fundus didn't change before & after treatment. There were no changes of ERG in 8 eyes of 4 cases. In addition, the advantages and disadvantages between Zn iontophoresis and Zn compound taken orally, the improvement of vision by direct electric current therapy, the relationship between the metabolism of Zn element and Vit A and influence of Zn over the mechanism of dark adaptation were also briefly discussed.

Adaptation, Ocular↗
PubMed1990

[Study on chromosome c-banding in Paragonimus westermani: comparison of the diploid and triploid types].

A comparative study was performed in detail on the c-band pattern of diploid and triploid types of Paragonimus westermani by using BSG method. The result revealed that both types of P. westermani possessed the identical c-band pattern and c-band polymorphism. Thus the authors considered that the triploid type of P. westermani might be an autotriploid. The polymorphism of c-band pattern in diploid and the combination of homologous chromosomes with c-band polymorphism in triploid were reported for the first time.

Animals↗
PubMed1990

[A preliminary study on the pharmacology of the compound prescription huangqin tang and its component drugs].

Results obtained from the pharmacological experiments demonstrated that the compound prescription Huangqin Tang and its component drugs, roots of Paeonia lactiflora, Scutellaria baicalensis and Glycyrrhiza uralensis, and the fruit of Ziziphus jujuba showed marked anti-inflammatory effect. The compound prescription and its component drugs, except the peony root, possessed significant antispastic effect. Antipyretic effect of Radix Scutellariae, Radix Glycyrrhizae and Huangqin Tang was suggested. Huangqin Tang, Radix Paeoniae alba, and Radix Glycyrrhizae showed marked analgesic effect. In addition, the experiments confirmed that both Huangqin Tang and single Radix Scutellariae have sedative effect.

Animals↗