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Biomedical subjects

D Liang

Publications and source records attributed to D Liang.

At least 19 recordsLinked to original sources
PubMed1996

Molecular replacement study on form-B monoclinic crystal of insulin.

The form-B monoclinic insulin crystal was obtained from the sodium citrate buffer with 1% zinc chloride, keeping phenolic content between 0.76% and 1.25%. Its space group is P2(1), cell constants are: a = 4.924 nm, b = 6.094 nm, c = 4.818 nm, beta = 95.8 degrees. There are 6 insulin molecules which form a hexamer. The initial phase was obtained by using rotation function program of X-PLOR program package and molecular packing program of our laboratory. The molecular model was chosen from 4 zinc bovine insulin hexamer. After the preliminary refinement by using the macromolecular rigid body refinement technique, the molecular model was further refined and adjusted by using the energy-minimizing stereochemically restrained least-squared refinement on the difference Fourier maps. The final R-factor is 22.4% at 0.3 nm resolution, the r.m.s. deviations from standard bond length and bond angle are 0.0022 nm and 4.7 degrees, respectively.

Crystallography↗
PubMed1995

Influence of preexistent donor coronary artery disease on the progression of transplant vasculopathy. An intravascular ultrasound study.

BACKGROUND: Transplant vasculopathy (TxCAD) limits longterm survival of allograft recipients. The possibility that preexistent donor coronary disease (PEDD) might accelerate this process is of concern. The serial progression of sites with and without PEDD as assessed by intravascular ultrasonic imaging is explored in this study. METHODS AND RESULTS: Thirty patients with baseline intravascular imaging within 3 weeks of cardiac transplantation who had at least one annual follow-up study were included in this study. Vessel luminal area (LA), total area (TA), intimal index (II = TA - LA/TA), mean intimal thickness (MIT), and Stanford classification were expressed for each image site and for each patient at each study. Progression of sites and of patients with and without PEDD on the baseline study was compared. Patients with PEDD (n = 9) still had significantly more intimal disease than those without PEDD (n = 21) at the first follow-up study (MIT = 0.35 +/- 0.13 versus 0.13 +/- 0.11 mm; II = 0.29 +/- 0.11 versus 0.11 +/- 0.1; class = 3.7 +/- 0.5 versus 2.2 +/- 0.94; P < .001 for all comparisons). However, the increase in intimal thickness during the 1- year interval was not significantly different between the two groups. In 4 patients in whom both types of sites were present, no difference in progression was found. Data were similar for patients and sites studied over > 1 year. CONCLUSIONS: PEDD does not accelerate the progression of TxCAD within the first few years after cardiac transplantation. The pathophysiology of TxCAD is most likely immune mediated and does not seem to be accelerated by native coronary artery disease.

Adult↗
PubMed1995

Application of chiral gas chromatography with electroantennographic detection to the determination of the stereochemistry of a cockroach sex pheromone.

The coupling of an electroantennographic detector to a chiral capillary gas chromatographic system provides a highly sensitive technique for the determination of pheromone stereochemistry. Electronic modification of the usual electroantennographic detector enables the detector to respond to the relatively broad peaks produced by chiral gas chromatographic systems. By using this methodology, supellapyrone, a female sex pheromone of the brownbanded cockroach Supella longipalpa (Orthoptera: Blattellidae), is shown to be 5-(2'R,4'R-dimethylheptanyl)-3-methyl-2H-pyran-2-one.

Animals↗
PubMed1995

The crystal structure of deshexapeptide (B25-B30) insulin at 0.25 nm resolution.

The determination of deshexapeptide (B25-B30) insulin (DHI) was divided into two steps. At the first step, the rough structure model of DHI molecule was determined by using the molecular replacement method associated with the molecular close-packing method at 0.30 nm resolution based on the reflection data collected on four-cycle diffractometer. At the second step, the DHI model was adjusted and refined at 0.25 nm resolution based on the data collected on Area Detector. 40 water molecules were determined during the refinement, the final R-factor is 0.185 with R.M.S. deviation of 0.002 nm for bond lengths and 1.9 degrees for bond angles. The differences in conformation and function of DHI with other insulin analogues were compared and discussed.

Insulin↗
PubMed1995

[Pharmacokinetics of ciprofloxacin injection in healthy volunteers].

The results of pharmacokinetic study of intravenous infusion ciprofloxacin in normal male volunteers were presented. Serum and urine concentrations of ciprofloxacin were determined by high performance liquid chromatography. The single dose 200 mg iv concentration-time curve fitted to two-compartment open model in eight volunteers. Its main pharmacokinetic parameters were: C0 4.61 +/- 1.64 mg/L, t1/2 beta 3.86 +/- 0.67 h and AUC 7.06 +/- 1.21 mg/L.h. The urinary recovery rate of ciprofloxacin over 12 h after dosing was 60.85%.

Adult↗
PubMed1995

[A multiple center clinical trial on fluconazole for deep-seated fungal infections].

A multiple center clinical trial was conducted to evaluate the efficacy and safety of domestic fluconazole in treating 913 cases of deep-seated fungal infections. Fluconazole was given 100-200 mg daily for 3 days to 8 months. The results showed that the cure rate and the total efficacy rate were 69.26% and 94.29% respectively. The fungal clearance rate was 93.83%. The main side-effects were nausea, vomiting, diarrhea and abdominal pain, but most of the patients could endure. The side-effect rate was 9.20%. This clinical trial indicated that domestic fluconazole was effective and safe in treating deep-seated fungal infections.

Adolescent↗
PubMed1994

High-performance liquid chromatographic assay of cefazolin in rat tissues.

A rapid, sensitive and reproducible high-performance liquid chromatographic (HPLC) assay for cefazolin in rat tissues was developed. Tissue samples were homogenized in distilled water, acidified with 8.5% phosphoric acid, and centrifuged. Cefazolin was isolated from the supernatant by solid-phase extraction on C18 cartridges. The eluate containing cefazolin and internal standard, cephalexin, was injected onto a reversed-phase C18 column and eluted with a mobile phase of 23% methanol in 0.02 M sodium phosphate monobasic (pH 5.0) and detected with UV absorbance at 270 nm. Recoveries of cefazolin were 33.7 +/- 2.5%, 45.4 +/- 2.1%, and 42.9 +/- 1.0% from liver, spleen and lung, respectively. The calibration curves for cefazolin were established at 0.5-1500 micrograms/g in spleen, 0.1-250 micrograms/g in liver and 0.1-75 micrograms/g in lung. The assay was reproducible with within-day and between-day variations of 1-2 and 1-4%, respectively. Application of the assay for tissue distribution of cefazolin in liposomal targeting study was demonstrated.

Animals↗
PubMed1994

Use of the four-and-a-half clearing technique to study gymnosperm embryology: Cunninghamia lanceolata.

Since its introduction in 1971, the four-and-a-half clearing technique has been widely applied to the study of ovule and female gametophyte development in flowering plants as an alternative to the more arduous paraffin section methods. The technique has undergone several modifications that have broadened its application in studies of Angiosperm embryology. To date, however, the technique has not been successfully applied to embryological features of Gymnosperms. Dark coloration caused by naturally occurring substances and by-products of fixation render the clearing fluid ineffective, and special pretreatment methods used to remove dark substances in Angiosperm ovules have little or no effect on Gymnosperm material. In the technique reported here, paraffin sections of ovules and young seeds of Cunninghamia lanceolata 80-120 microns thick are cleared in benzyl benzoate-4 1/2 clearing fluid and examined with phase contrast optics. Observations of the mature female gametophyte in these cleared preparations are compared with those obtained from 10 microns sections, stained with safranin and fast green, and examined with bright-field optics. Although contrast and definition are more pronounced in stained sections than in cleared ones, the differences would not alter one's interpretation of characteristic structural features. The thick, cleared section offers an advantage over the thin, stained one in that many structural entities are contained within a single section rather than spread through several serial sections. The time required for clearing thick sections is much shorter than that required for making permanent stained preparations.

Microscopy↗
PubMed1993

[Study on the relationship between appearance of autoantibodies and chest X-ray findings of asbestos plant employees].

Antinuclear factor (ANA) and rheumatoid factor (RF) were determined in 220 employees of an asbestos plant. The relationship of the appearance of the two factors to sex, age, smoking habit, duration of asbestos exposure and asbestos exposure level was studied. In 207 employees who had chest roentgenograms, the relationship of these two factors to pulmonary lesions and pleural lesions was examined. Of the 220 employees, 33 (15%) had ANA and 7 employees (3.2%) had RF. ANA positive rate in the asbestos plant employees was significantly higher than in the control. Factors significantly correlated to their appearance could not be demonstrated. With the progress of pulmonary lesions the ANA positive rate significantly elevated, but ANA positive rate was not significantly correlated with pleural lesions. RF did not show any significant correlation with any of the factors.

Adult↗
PubMed1993

[Experimental observation on the relation between pericardium meridian and cardiac function].

The theory of Traditional Chinese Medicine (TCM) holds that "internally, meridians connect with the visceral organs, and externally, with the joints, limbs and other superficial tissues of the body". The results of the investigations on the meridian phenomena, including propagated sensation along meridians (PSM) and others, also showed that certain lines or tracks, coincident with the course of classical meridians, really existed over the body surface. In order to probe into the relation between the pericardium meridian, acting as a organic whole, and the cardiac function, 100 cases of patients suffering from coronary heart disease, with or without PSM, were observed on the one and the same subject before and after acupuncture for comparison. Four acupoints, namely Neiguan (PC6), Ximen (PC4), Quze (PC3), Tianquan (PC2) and two other non-acupoint spots on the Pericerdium Meridian of the same person were acupunctured in different days respectively. At the same time, the spots locating on the both sides of above 4 acupoints, with a distance of 1.5-2.0 cm from them former, and Guangming (GB37) of Gall-Bladder Meridian were taken as controls. Electrocardiogram, cardiophonogram and rheocardiogram were recorded simultaneously. Taking PEP, LVET, P/L, HI, SV, CO, ST segment and T wave of ECG as indexes for analysis, the effect of acupuncture of acupoints on Pericardium Meridian and controls were compared. The results of 737 times of observation demonstrated that the 8 indexes of 4 acupoints and other two non-acupoint spots on the Pericardium Meridian all changed conspicuously after acupuncture. However, the changes of above indexes of the controls, including 8 spots beside Pericardium Meridian, were slight.(ABSTRACT TRUNCATED AT 250 WORDS)

Acupuncture Points↗
PubMed1993

[The difference in the time for the appearance of acupuncture effects between the subjects with and without PSM during acupuncture of neiguan].

It has been reported that ECG of the patients of coronary heart disease with PSM got marked improvement when Neiguan (PC6) was punctured, in comparison with the patients without propagated sensation along meridians (PSM). The difference between the two was significant. However some others reported that the acupuncture effects between the two had no striking difference. Authors detected that during acupuncture of Neiguan the change of ECG of the patients showed dynamic character and some patients without PSM were also marked as the duration of acupuncture was prolonged. For this reason, this paper was aimed to observe whether any difference appeared in the development of acupuncture effects between the patients with and without PSM. One hundred and seventy cases of patients with coronary heart disease were observed, of which 86 were male and 84 female, aged 35-83 years. Varying degree of PSM appeared in 80 of them, but not in the remaining 90. ECG was recorded with polygraph (model SJ-42) before acupuncture. Then the Neiguan acupoint of the left forearm was punctured by slow twisting for 5 minutes and the feature of PSM was carefully observed. Another recording of ECG was taken after retaining needle for 10 minutes. Retaining needle lasted for 30 minutes in a part of the patients and the needle was manipulated every 16 minutes in order to keep the needling sensation.(ABSTRACT TRUNCATED AT 250 WORDS)

Acupuncture Therapy↗
PubMed1993

Parallel decrease of Na(+)-taurocholate cotransport and its encoding mRNA in primary cultures of rat hepatocytes.

We investigated the molecular mechanism underlying the progressive loss of Na(+)-dependent bile salt uptake in primary cultured rat hepatocytes. A specific cDNA probe was used to quantitate the levels of mRNA encoding the Na(+)-taurocholate-cotransporting polypeptide at various culture times. Hepatocytes were cultured on collagen in the presence of insulin (10(-7) mol/L), dexamethasone (10(-7) mol/L) and 10% fetal calf serum for up to 72 hr. During this time period the dissociation constant of Na(+)-dependent taurocholate uptake remained stable (19 to 39 mumol/L), whereas the maximum velocity values decreased from 100% at 3 hr to 55%, 22% and 4% at 24, 48 and 72 hr, respectively. Concomitantly the levels of the Na(+)-taurocholate-cotransporting polypeptide mRNA also decreased from 100% at 3 hr to 41%, 24% and 4% at the later time points. In contrast, Northern hybridization with complementary DNA probes for three common housekeeping gene products revealed a 1.8- to 3.4-fold increase in the levels of mRNA encoding the alpha-subunit of the Na+K(+)-ATPase, beta-actin and glycerol-3-phosphate dehydrogenase. These data indicate that the loss of Na(+)-dependent bile salt uptake in primary cultures of rat hepatocytes is caused by decreased levels of its specific mRNA. Hence the studies further confirm that without specific measures (primary) cultured rat hepatocytes reverse their liver-specific phenotype to a more fetal pattern of gene expression.

Animals↗
PubMed1993

[Pharmacokinetics of ciprofloxacin in young healthy volunteers].

Pharmacokinetic studies on ciprofloxacin were carried out in 6 young healthy volunteers. Serum and urine levels of ciprofloxacin were measured by reversed-phase high performance liquid chromatography. The drug obeyed one-compartment model kinetics in serum. The mean peak serum concentration, time to peak concentration and the area under the curve were 4.17 +/- 1.05mg/L, 1.75 +/- 0.40h and 18.09 +/- 2.69mg/L.h respectively after oral administration of 500mg of ciprofloxacin tablet. The elimination half life was 2.34 +/- 0.81h and the apparent volume of distribution was 3.71 +/- 0.75L. The urinary rate of ciprofloxacin over 24h after dosing was 34.22 +/- 6.57%. These data indicate that ciprofloxacin is easily absorbed and its concentration reaches the peak level rapidly. There are high levels of drug both in serum and urine.

Adult↗
PubMed1993

[Effect of verapamil with renal disease basic-prescription on hemorheology indexes of type II nephrotic syndrome].

24 cases of type II nephrotic syndrome were studied and divided randomly into two groups. Group A: 12 cases treated with verapamil; Group B: 12 cases treated with verapamil plus Renal Disease Basic-prescription (RDBP). Hemorheology indexes were measured in the two groups before and 4 weeks after the treatment. The results showed hyperviscosity was obviously improved in group A after verapamil administration (P < 0.05), but the improvement in group B was much more significant than that in group A. The results mentioned above indicate that calcium channel blocker has an anticoagulant effect with inhibiting platelet aggregation, and Peach kernel, Safflower, etc of RDBP played a role in prohibiting platelets aggregation, anticoagulation and promoting microcirculation. However the combination of the two methods has better effect in improving the hypercoagulable state of nephrotic syndrome.

Adolescent↗
PubMed1993

[Determination of ciprofloxacin in human serum and urine by reversed-phase HPLC].

A sensitive and rapid method for the determination of ciprofloxacin using enoxacin as the internal standard was reported. High-performance liquid chromatograph model 344 (Beckman, USA) with a variable wavelength UV detector and reversed-phase Ultrasphere-ODS column (5 microns, 250 x 4.6 mm) was used. Serum or urine sample preparation involved addition phosphate buffer (pH 7.5) and aqueous solution of sodium lauryl sulfate, followed by chloroform extraction. The organic layer was removed and evaporated to dryness under an air stream in a 37 degrees C water bath. The residue was dissolved in 50 microliters mobile phase and 20 microliters injected. The mobile phase of 0.02 mol/L acetate buffer (pH 3.0) -acetonitril-dimethylformamide-10% aqueous solution of tetrabutyl ammonium hydroxide (88:6.5:5:0.5) was pumped at 0.9 ml/min through the column. The detector operated at 0.01 aufs and the wavelength was set at 276 nm. The retention times for ciprofloxacin and enoxacin were 7.31 min and 5.59 min, respectively. In serum, standard curve was linear in the concentration range of 0.75 to 24 mumol/L, the detective limit was 0.2 mumol/L, extraction recovery was 69-74%, within-day CV was less than 5%, and inter-day CV was less than 6%.

Chromatography, High Pressure Liquid↗
PubMed1993

Mitochondrial dysfunction in alcoholic patients as assessed by breath analysis.

Mitochondria of patients with alcoholic liver disease are morphologically abnormal, and mitochondria isolated from animals exposed to ethanol exhibit functional deficiencies in vitro. Because the functional consequences of the morphological alterations and the relevance of in vitro observations to mitochondrial function in alcoholic subjects are not clear, we assessed mitochondrial function noninvasively with a breath test. Mitochondrial function was assessed by measuring the exhalation of 14CO2 after administration of 1 microCi 2-keto[1-14C]isocaproic acid, the decarboxylation of which occurs in mitochondria. The results of the 2-keto[1-14C]isocaproic acid breath test in 17 alcoholic subjects were compared with the results in healthy controls and patients with nonalcoholic liver disease. The peak exhalation of 14CO2 and the fraction of the administered dose decarboxylated in 60 min were significantly lower in alcoholic patients than in healthy controls or patients with nonalcoholic liver disease. In alcoholic patients 2-keto[1-14C]isocaproic acid decarboxylation was impaired in the presence of normal conventional and quantitative liver function as assessed by aminopyrine breath test and galactose elimination capacity, indicating that 2-keto[1-14C]isocaproic acid decarboxylation does not simply reflect decreased functional liver mass. We conclude that mitochondrial function as reflected by 2-keto[1-14C]isocaproic acid decarboxylation is impaired in chronic alcoholic patients. The functional impairment is specific for excessive ethanol consumption and not a reflection of decreased global liver function or the presence of cirrhosis. 2-Keto[1-14C]isocaproic acid decarboxylation could thus be useful as a marker of excessive ethanol consumption.

Adult↗
PubMed1992

Protective effects of the calcium antagonists diltiazem and TA3090 against hepatic injury due to hypoxia.

Recent work has shown that dihydropyridine-type calcium channel blockers such as nitrendipine protect against ischemic liver damage in the rat in vivo (Thurman RG, Apel E and Lemasters JJ, J Cardiovasc Pharmacol 12: S113-S116, 1988), suggesting that calcium antagonists may have clinical value in preventing ischemic and hypoxic hepatic injury. This study was designed to examine the effects of two benzothiazepine-type calcium channel blockers, diltiazem and TA3090, in the hypoxic perfused rat liver. Livers were isolated and perfused briefly with oxygen-saturated buffer, followed by perfusion for 80 min with nitrogen-saturated buffer with diltiazem or TA3090 (20-200 microM), and concluding with 20 min of perfusion with oxygen-saturated buffer. In control preparations, maximal lactate dehydrogenase (LDH) release into effluent perfusate following hypoxia averaged about 1100 U/L. Diltiazem and TA3090 decreased LDH release at all concentrations studied; both drugs were most effective at the 100 microM concentration (71 and 73% inhibition, respectively). Oxygen uptake by control livers decreased 78% following hypoxia; diltiazem and TA3090 reduced this effect markedly, with maximal effectiveness again observed with 100 microM (O2 uptake was decreased by 22% with 100 microM diltiazem and by only 9% with 100 microM TA3090). Histological examination for nuclear uptake of the vital dye trypan blue revealed necrosis of parenchymal cells along with cell shrinking and consequent expansion of the sinusoids in control livers. Perfusion with diltiazem markedly reduced parenchymal cell death but did not alter the pattern of cell damage observed. In contrast, livers perfused with TA3090 during hypoxia had virtually no parenchymal cell damage, although moderate damage to nonparenchymal cells in the sinusoids occurred. The difference in mechanisms responsible for the phenomena which occur with diltiazem and TA3090 is not completely understood; however, these and other calcium antagonists clearly have powerful hepatoprotective effects against ischemia and hypoxia.

Animals↗