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Biomedical subjects

J Zhu

Publications and source records attributed to J Zhu.

At least 793 records · Page 44Linked to original sources
PubMed1990

[Immunoregulation disturbance in experimental allergic neuritis. The cellular and humoral mediated immunological damage].

The cellular and humoral mediated immune responses were investigated in the rabbits with experimental allergic neuritis (EAN) induced by the myelin basic protein (MBP) purified from the human sciatic nerve. The cellular mediated immunity to MBP were assayed by skin testing and lymphocytes transformation. The antibodies to myelin and muscle, the immunoglobulin deposits in the nerve and tissues respectively were detected by indirect and direct immunoenzyme assays. In rabbits with EAN, the skin tests became positive at the onset of EAN. There was a significantly higher index of the lymphocytes transformation in the EAN than in normal animals. At the height of the disease, the anti-muscle antibody titres were high. The granular deposits containing IgG were found in sciatic nerve and heart. The results favour cellular and humoral mediated immunological damage as the most important pathogenetic mechanism in EAN.

Animals↗
PubMed1990

Prophylactic oral naltrexone with epidural morphine: effect on adverse reactions and ventilatory responses to carbon dioxide.

The influence of two different doses of oral naltrexone on the adverse effects and the analgesia of epidural morphine were compared in a double-blind, placebo-controlled study. Forty-five patients undergoing cesarean section were provided postoperative analgesia with 4 mg epidural morphine. Five minutes later they received 6 mg naltrexone, 9 mg naltrexone, or placebo as an oral solution. Pain relief was assessed by the Visual Analog Scale (VAS) and by direct questioning of the patients. Requirement for additional analgesics and side effects were noted. Respiratory effects of epidural morphine and naltrexone were assessed using the ventilatory responses to CO2 and by monitoring O2 saturation (Spo2) using pulse oximetry. All patients in the placebo group had adequate analgesia. One of the 15 patients who received naltrexone 6 mg had inadequate analgesia versus five of the 15 patients who received naltrexone 9 mg (P less than 0.05), 9 mg versus placebo. Ten patients (67%) in the placebo group had pruritus while no patient in the 6 mg naltrexone group and one patient in the 9 mg group experienced mild pruritus (P less than 0.05), placebo versus other two groups. The CO2 response slopes were depressed compared to control values from 6-16 h in the placebo group, from 6-12 h in the 6 mg naltrexone group. No significant depression was noted in the 9 mg naltrexone group. The authors conclude that oral naltrexone 6 mg significantly reduces the incidence of pruritus associated with epidural morphine without affecting analgesia and that 9 mg naltrexone is associated with shorter duration of analgesia than 6 mg naltrexone.

Administration, Oral↗
PubMed1990

[Effects of noradrenaline and dopamine in preoptic area on acupuncture analgesia].

Previous work has shown that activation of catecholamine in the preoptic area is to the disadvantage of acupuncture analgesia. In this work microinjection and push-pull perfusion as well as HPLC-ECD were used to observe the effect of noradrenaline and dopamine in this area on acupuncture analgesia. The results indicated that microinjection of noradrenaline (0.5 microgram/unilateral) into the preoptic area could attenuate acupuncture analgesia, while dopamine (2 micrograms/unilateral) had no effect on acupuncture analgesia. During acupuncture analgesia, the contents of noradrenaline and MHPG in the perfusate from the preoptic area were markedly decreased, and that of dopamine, however, was not changed significantly. The above results suggest that activating noradrenaline, but not dopamine, exerts antagonistic effect on acupuncture analgesia.

Acupuncture Analgesia↗
PubMed1989

The biosynthesis and actions of prostaglandins in the renal collecting tubule and thick ascending limb.

PGE2 formed by renal collecting tubules is an important factor in regulating NaCl and water reabsorption in the collecting tubule and medullary thick ascending limb. PGE2 appears to act, depending on its ambient concentration, via several different receptors present in these renal epithelia to modulate cAMP turnover in both positive and negative directions. These putative PGE receptors form a family of receptors, all coupled to G proteins, and this family of PGE receptors is homologous to the adrenergic receptor family.

Animals↗
PubMed1989

Isoflurane or halothane for cesarean section: comparative maternal and neonatal effects.

The maternal and neonatal effects of isoflurane and halothane combined with 50% N2O - 50% O2 were compared in 60 healthy parturients undergoing primary or repeat cesarean section. All patients had rapid sequence induction of anesthesia with sodium thiamylal 4 mg/kg followed by succinylcholine for tracheal intubation. Patients were randomly assigned to one of three groups of 20 each (inspired 0.5% isoflurane, 1% isoflurane or 0.5% halothane), combined with 50% N2O and O2. After delivery, 67% N2O in O2 was used, supplemented by butorphanol. Maternal blood loss did not differ significantly among the three groups and none of the patients developed intraoperative awareness. At the time of delivery, maternal plasma epinephrine levels were significantly above preinduction levels in the 0.5% isoflurane group but unchanged in the other two groups. Neonatal status as ascertained by Apgar scores, cord acid base status and the Neurologic and Adaptive Capacity Scores (NACS) was equally good in the three groups of patients. Serum inorganic fluoride concentrations in the mother after anesthesia were not significantly above preanesthetic levels in any of the groups and there was no biochemical evidence of renal toxicity. In all neonates fluoride ion concentrations in the first voided urine sample were less than 7 mumol/l, a value well below that associated with nephrotoxicity. It is concluded that isoflurane is a safe supplement to N2O - O2 mixture for cesarean section and is a safer alternative to halothane in situations when patients receiving beta-adrenergic therapy require cesarean section since halothane might potentiate arrhythmias caused by beta adrenergic agonists.

Adult↗
PubMed1989

[The facilitatory effect of sympathetic efferents on sustained discharges of polymodal nociceptors].

Injection of a compound algogenic substance into receptive field of the skin induced sustained discharges of polymodal nociceptors in rats. The sustained discharges were obviously increased by stimulation of the sympathetic nerve innervating the receptive field. Initial facilitation was followed by the inhibition of discharges in partial units. The sympathetic effect can be activated repeatedly and lasted for a prolonged time. Injection of norepinephrine (5 micrograms/0.2 ml) into the local artery could cause the similar effect. Results indicate that the sympathetic efferents facilitates the sustained discharges of polymodal nociceptors. The possibility of producing causalgia and contrary results of experiments were discussed.

Animals↗
PubMed1988

Mini-dose intrathecal morphine for the relief of post-cesarean section pain: safety, efficacy, and ventilatory responses to carbon dioxide.

To determine the safety, efficacy, and the ventilatory responses to carbon dioxide (CO2) of mini-dose intrathecal morphine, 33 healthy women who underwent cesarean section with spinal anesthesia using 0.75% bupivacaine in 8.25% dextrose were studied. Patients were randomly assigned to receive, in a double-blind fashion, either morphine 0.25 mg (group I, n = 11), morphine 0.1 mg (group II, n = 10), or saline (group III, placebo group, n = 12) in 0.5 ml volume mixed with the bupivacaine. In both groups I and II excellent postoperative analgesia with long duration was obtained (27.7 +/- 4.0 and 18.6 +/- 0.9 hours, respectively, X +/- SEM). All patients in group III required an analgesic (8 mg subcutaneous morphine) within 3 hours of spinal anesthesia. Seven patients in group I and four patients in group II developed mild pruritus that did not require treatment. Ventilatory responses to CO2 showed no evidence of depression attributable to either the 0.25 or 0.1 mg of morphine, but significant depression of the CO2 responses was observed in group III patients after administration of subcutaneous morphine. It is concluded that a dose as low as 0.1 mg of intrathecal morphine gives excellent analgesia with minimal to no side effects and that subcutaneous morphine is associated with marked depression of the ventilatory variables.

Adult↗
PubMed1987

Effects of the coherence of illumination on electron microdiffraction pattern intensities.

Microdiffraction is capable of revealing the local structure within an area of the specimen consisting of only a few, or a few tens of, unit cells. However, the extent to which the diffraction pattern intensities can show the local structure depends strongly on the coherence of the illumination. If the coherence width of the illumination is smaller than the diameter of the electron probe at the specimen level, the details within the diffraction spots, which indicate deviations of the local structure from the periodicity of the crystal, will be lost. The differences in the amount of spot splitting observed in microdiffraction patterns from out-of-phase domain boundaries, observed with two instruments, are attributed to differences in the effective source sizes.

Computer Simulation↗
PubMed1987

Microdiffraction and analysis.

The intensity distribution in the microdiffraction pattern depends strongly on the coherence of the illuminated source. The coherence width at the specimen level is considered as a parameter to check the coherence of an electron microscope. Two application examples are illustrated. A small interphase precipitate of MgNi2 in an Ni superalloy has been identified by a combination of microdiffraction and energy dispersive spectrum (EDS) techniques, though it can not be found by conventional transmission electron microscopy (TEM) and selected area diffraction (SAD). By means of microdiffraction as well as high-resolution electron microscopy (HREM) imaging a defect structure has been determined. Such a defect makes the lattice extinction spots appear with various intensities in the selected area diffraction and microdiffraction patterns.

Electron Probe Microanalysis↗
PubMed1987

Predictors of efficacy of amiodarone and characteristics of recurrence of arrhythmia in patients with sustained ventricular tachycardia and coronary artery disease.

The value of serial electropharmacologic testing during long-term oral amiodarone therapy for prediction of long-term drug efficacy as well as characteristics of arrhythmia recurrence is controversial. One-hundred four consecutive patients with coronary artery disease and sustained ventricular tachyarrhythmias (VT) underwent initial electrophysiologic (EP) evaluation in the drug-free state and again after an amiodarone loading period of 25 +/- 14 days (mean +/- SD). Twenty-six patients (25%) had no inducible ventricular tachyarrhythmia during therapy with amiodarone (VT control group), whereas arrhythmia inducibility persisted in the remaining 78 patients (VT noncontrol group). During 17.4 +/- 13.7 months of follow-up, two patients in the VT control group either had VT recurrence or died suddenly compared with 21 VT recurrences and eight sudden cardiac deaths in the VT noncontrol group (actuarial event rates at 36 months of 0.11 and 0.56, respectively, p = .0065). The cycle lengths of recurrent VT in these 21 patients in the VT noncontrol group were compared with those observed at final EP testing. A significant linear correlation was demonstrated (r = .76, p = .0001). Subgroup analysis of patients in the VT noncontrol group showed no EP predictors of outcome, including cycle length of induced VT. However, patients dying suddenly during the follow-up period had a higher prevalence of new or worsening congestive heart failure (75%) compared with patients with VT recurrence (19%) or those with no arrhythmic event (29%) (p less than .02).2off

Aged↗
PubMed1987

Comparative maternal, fetal, and neonatal effects of chloroprocaine with and without epinephrine for epidural anesthesia in obstetrics.

The effects of epidural chloroprocaine with and without 1:200,000 epinephrine during labor and delivery on uterine activity, progress of labor, fetal heart rate, maternal blood pressure, newborn Apgar scores, neonatal acid-base status, and the Neurologic and Adaptive Capacity Scoring System (NACS) were compared in 28 parturients. Patients in group I (n = 14) received 2% chloroprocaine with 1:200,000 epinephrine and patients in group II (n = 14) received 2% plain chloroprocaine. Addition of epinephrine to chloroprocaine had no significant effects on uterine activity, duration of first or second stages of labor, or fetal heart parameters. Apgar scores, neonatal acid-base status, and the NACS were equally good in the two groups. Duration of analgesia was significantly longer in group I than in group II patients (76 +/- 3.8 vs 42.9 +/- 1 min, P less than 0.001). We conclude that addition of epinephrine to chloroprocaine during epidural anesthesia in the normal parturient has no adverse effects on mother, fetus, neonate, or the progress of labor and that it significantly prolongs the duration of anesthesia.

Acid-Base Equilibrium↗
PubMed1987

Epidural butorphanol or morphine for the relief of post-cesarean section pain: ventilatory responses to carbon dioxide.

To determine the safety, efficacy, and the ventilatory responses to carbon dioxide (CO2) of epidurally administered butorphanol or morphine, 122 healthy women who underwent cesarean section with epidural anesthesia were studied. Patients were randomly assigned to receive one of four epidural regimens for the relief of postoperative pain: 5 mg morphine (n = 32), 4 mg butorphanol (n = 30), 2 mg butorphanol (n = 29), or 1 mg butorphanol (n = 31). Epidural morphine provided satisfactory analgesia with slow onset and long duration of approximately 21 hr. When butorphanol was administered, analgesia of rapid onset was seen with increasing duration and effectiveness observed with increasing dose; approximately 8 hr when using 4 mg. Sixty-two percent of the patients who received morphine had pruritus. Somnolence was the main side effect encountered in patients who received epidural butorphanol. The ventilatory response to CO2 was depressed after morphine and after 2 and 4 mg butorphanol, but the duration of depression was more prolonged after morphine. It is concluded that epidural butorphanol is effective in providing pain relief after cesarean section with minor side effects. However, patients must be observed closely because of possible respiratory depression.

Butorphanol↗
PubMed1986

Construction of stable laboratory and industrial yeast strains expressing a foreign gene by integrative transformation using a dominant selection system.

An expression cassette of mouse dihydrofolate reductase (Mdhfr) cDNA under control of the yeast cytochrome c promoter was inserted in a yeast plasmid containing the ARS1 sequence. The ARS replicating function was destroyed by BglII treatment prior to yeast transformation. Using this linearized plasmid, genomic transformants could be obtained from either laboratory or industrial strains of bakers' yeast based on direct methotrexate (MTX)-resistance selection. The entire sequence of the linearized plasmid was integrated by homologous recombination at the ARS region of the host chromosome. The results indicate that repetitive and homologous recombination occurs readily in such transformations. The stability of the constructed integrants was more than 99.95% per generation in non-selective medium, and tandem repeats of up to six copies (i.e., about 44 kb) were not changed even after 30 generations in rich medium. Expression in rich medium of cointegrated, human interleukin 2 cDNA under control of the triose phosphate isomerase promoter was shown by Western blot experiments in both laboratory and industrial yeast strains. Furthermore, a comparison of the transcription efficiency of the Mdhfr gene in the chromosome with that in the plasmid revealed that the efficiency was almost proportional to the number of gene copies, irrespective of the location of the transcription unit. These results show that by using the MTX/Mdhfr dominant selection-amplification system one can construct stable recombinant yeast strains suitable for heterologous gene expression in laboratory as well as in industrial fermentation conditions.

DNA, Fungal↗