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Biomedical subjects

D Xu

Publications and source records attributed to D Xu.

At least 415 records · Page 23Linked to original sources
PubMed1990

[Diagnostic value of transbronchial lung biopsy in diffuse or peripheral lung lesions].

The results of 102 cases of diffuse or peripheral lung lesions examined by transbronchial lung biopsy (TBLB), bronchial brushing (BB), and bronchial alveolar lavage (BAL) via fiberoptic bronchoscope, were reported. The positive diagnostic rate was 74.5% (76 cases). In lung cancer, the positive rate by means of BB was 77.1%, which was higher than that by TBLB (58.1%). In pulmonary tuberculosis, the positive rate by TBLB was 76.9%, higher than that by BAL fluid for identification of tubercle bacillus by culture (44.4%). If TBLB was combined with BB and BAL, the positive diagnostic rate would be further elevated. The data showed that if the size of the masses greater than or equal to 3cm in peripheral lung field on chest film, the possibility of lung cancer was greater than that of those less than 3cm. Most cases of localized infiltration in the lungs were caused by tuberculosis. But the diffuse lesions of the lungs were often caused by bronchiolo-alveolar carcinoma, adenocarcinoma, diffuse interstitial fibrosis of the lungs, silicosis, sarcoidosis, etc. By the careful study of the chest film and ascertainment of the exact locations of the pulmonary lesions there, we can carry out the TBLB and obtain a satisfactory specimen without any X-ray monitoring. In the present group of patients who underwent TBLB, one was complicated by haemorrhage (greater than 50ml) and two by pneumothorax, but all of them recovered promptly after proper management. By strick adherence to indication, adequate preoperative preparations and very careful performance of the procedure, the complications of TBLB could be reduced to minimum.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Effect of seed soaking in plant hormone and trace element fertilizer on the growth of Psoralea corylifolia L].

Our study shows that seed soaking in triacontanol, ammonium molybdate and gibberellin can promote the growth of P. corylifolia, reduce its premature flower and fruit drop, raise the fruit-bearing rate by 6.5-17.4%, and fruit-bearing number by 21.6-28.4%, so as to increase the yield per unit area by 31.5-34.8%. Seed soaking in naphthylacetic acid and boric acid does not give such a marked effect.

Fabaceae↗
PubMed1990

[The effect of China-made amrinone on myocardial infarction and arrhythmia in dogs].

Six dogs underwent 15 min left anterior descending (LAD) coronary artery occlusion (CAO) with 1 hour's reperfusion for 3 times. Fifteen min after CAO (control), CAO during amrinone (Amr), and CAO during isoprenaline, sigma ST (mV) and ST (mV) were 66 +/- 26 and 8 +/- 2.72 +/- 61 and 9 +/- 4.90 +/- 48 and 11 +/- 6 respectively, 24h after LAD CAO, dP/dt max (kPa/s) and HR (heart beats/min) were 483 +/- 93 and 211 +/- 36 respectively. Intravenous Amr by 1, 5, 3 and 6 mg/kg increased dP/dt max to 630 +/- 79, 583 +/- 116 and 500 +/- 148; HR to 223 +/- 44, 232 +/- 45 and 239 +/- 54; and also decreased SBP, DBP and LVEDP. Amr caused neither change in percentage of non-sinus beats, nor ventricular fibrillation. These results suggested that in myocardial infarction and arrhythmia, Amr could still be of positive inotropic effect. Amr worsened myocardial infarction in nonfailing heart, but it did not aggravated arrhythmia after myocardial infarction.

Amrinone↗
PubMed1990

[Biological characteristics of Psoralea corylifolia L].

A study has been made on the biological characteristics of Psoralea corylifolia under general cultivating conditions. To search for the laws of growth and development so as to facilitate further studies on the cultivating techniques for higher production of Psoralea corylifolia.

Fabaceae↗
PubMed1990

Studies on the relationship between chromosome No15 and the biological characteristics of malignant transformed Syrian hamster fibroblast cell lines.

During the course of malignant transformation of mammalian cells in vitro, a regular variation in chromosome number and structure is usually found. In order to elucidate the relationship between chromosomal changes and malignant expression, we isolated five clones from a malignant transformed Syrian hamster fibroblast cell line and analysed their biological characteristics, as well as chromosomal changes. A positive correlation between chromosome No 15 monosomy and the transformed and malignant phenotype was observed. We suggest that a suppression gene may be located on chromosome No 15, and its deletion or the loss of the chromosome may result in expression of the malignant phenotype.

Animals↗
PubMed1989

Clinical, pathological and photochemical studies of laser injury of the retina.

Nineteen cases of acute accidental laser injury of the human retina and two groups of laser workers with chronic retinal damage were reviewed. Most acute cases had macular injury and vision impairment; the chronic cases usually suffered from nonspecific eye complaints. Pathological and photochemical studies of laser injury to rabbit retina were also made following exposure to a 0.49-W Ar laser. The retinal pigment epithelial cells and photoreceptors were mildly damaged in the laser spot center, but the Bruch's membrane was still intact. Malondialdehyde (MDA), the main degradation product of lipid peroxidation of the retina, was assessed with fluorescence spectrophotometry. The level of MDA in the injured retina was significantly higher than that in control eyes, suggesting that thermal levels of Ar laser exposure can yield evidence of photochemical light damage mechanisms.

Adult↗
PubMed1989

Ficoll-Hypaque leukocyte preparations from burned patients contain activated nonlymphoid cell populations that take up thymidine.

Previously, we reported that Ficoll-Hypaque-purified leukocytes from burned patients were activated in vivo, even when the mitogen response of these cells was depressed. In these patients, the SBT (endogenous blastogenesis), but not the mitogen response predicted sepsis. The current experiments were performed to clarify why the SBT is increased even when mitogen-stimulated blastogenesis is impaired. We found that neither selective lymphocyte subpopulation (OKT3, T4, T8), nor macrophage depletion returned the increased SBT to normal and that by phenotype and flow cytometric morphology, the Ficoll-Hypaque-purified leukocyte preparations of the burned patients contained fewer lymphocytes than controls (p less than 0.001). Discontinuous Percoll gradients and sheep-RBC rosetting were used to determine the relative contribution of T cells and non-T cells to the increased SBT. These studies indicated that both T cells and non-T cells were activated; however, the non-T cells were primarily responsible for the increased SBT. Thus the peripheral blood of burned patients contains a large fraction of metabolically active non-mononuclear cells that cosediment with mature lymphocytes and could result in artifactual alterations in the assessment of lymphocyte function by in vitro tests.

Adolescent↗
PubMed1989

Connective tissue of the livers of newborn and adult marmosets (Callithrix jacchus).

Immunofluorescence microscopic and electron microscopic investigations revealed components of the matrix and of the basal lamina (collagen type I, III, IV and V, BL-heparan sulfate and fibronectin) in the sinus wall (Disse's space) of the livers of newborn and adult marmosets (Callithrix jacchus). Collagen type I was missing in both the two age groups. Small amounts of laminin were present in the livers of newborn and absent in those of adult animals, whereas collagen type III occurred in the form of delicate fibres. Light microscopic inspection showed a continuous distribution of all other components in the sinus wall. The amount of collagen type III and V increased depending on the age. Electron microscopic investigations revealed single or bundled fibrils (20-30 nm) and filaments (10-12 nm). After addition of tannic acid, plaques of a fine-filamentous network and incorporated granules were observed. After addition of resting Ruthenium Red, electron-dense granules (20-60 nm) were irregularly distributed in the structureless space, resting on collagenous fibrils and cell membranes. The fibrils were allocated to collagen type III, the filaments to collagen type V. The plaques were supposed to contain heparan sulfate, collagen type IV and fibronectin. The absence of a Lamina densa of the basal lamina was attributed to the absence of laminin which probably plays an important role in the formation of this layer. Differences in the distribution pattern of the matrix components and thus a functional mosaic of the permeability of Disse's space were assumed. The complete absence of collagen type I and laminin in the lobules makes the adult marmoset liver especially suited for studies on the importance of this collagen type under pathological conditions, since both components are expressed in this way.

Animals↗
PubMed1989

Calcitonin gene-related peptide in the pathogenesis and treatment of hypertension.

The present study demonstrated that the plasma calcitonin gene-related peptide (CGRP) concentration was lower but the CGRP content of abdominal aorta was higher in spontaneously hypertensive rats (SHR) than in normotensive rats (WKY), using specific CGRP radioimmunoassay (P less than 0.01). In eighteen patients with essential hypertension, the concentration of plasma CGRP was also much lower than that of normal subjects, suggesting that a decreased release of arterial CGRP might be a part of the pathogenesis of essential hypertension. In SHR, a significant decrease in blood pressure was found following intravenous injection of 2.5 micrograms/kg of CGRP; similarly, in seven patients with essential hypertension intravenous injection of CGRP (50 micrograms) could induce a significant hypotensive effect. These data suggest that CGRP is a new potential drug for the treatment of essential hypertension.

Adult↗
PubMed1989

[Atrial natriuretic polypeptide in the human and rat spinal cord].

The widespread distribution of atrial natriuretic polypeptide (ANP) immunoreactive material was demonstrated in the human and rat spinal cord, using specific immunogold-silver staining technique and radioimmunoassay. Immunogold-silver staining studies showed that ANP immunoreactive neurons were quite prevalent in the human spinal cord. ANP immunoreactive neurons were largely found in the ventral horn and less in the dorsal and lateral horns. ANP immunoreactive material was absent with anti-ANP serum preabsorbed with ANP. In rats, radioimmunoassay demonstrated that ANP immunoreactive material was present in whole spinal cord. The highest concentration was found in the sacral spinal cord (21.9 +/- 4.48 ng/g tissue), the moderate in the lumbar (3.78 +/- 0.74 ng/g tissue) and the lowest in the cervical and thoracic (0.58 +/- 0.14 and 0.46 +/- 0.21 ng/g tissue, respectively). Gel chromatography and reverse-phase HPLC revealed multiple molecular forms in the rat spinal cord, but the main molecular form was the 28 amino acid rANP. In vivo study showed that ANP was released from the rat spinal cord by depolarizing concentration of potassium.

Animals↗
PubMed1989

[Calcitonin gene-related peptide in normotensive and spontaneously hypertensive rats].

Using specific radioimmunoassay, radioimmunoreceptor analysis and gel filtration, we found that calcitonin gene-related peptides (CGRP) were distributed in various tissues of normotensive rat (WKY) and spontaneously hypertensive rat (SHR), the highest content was in the lumbar spinal cord (1197 +/- 94.8 pg/mg tissue), the lowest in the auricle (15.0 +/- 2.1 pg/mg tissue). Compared with WKY, the plasma CGRP concentration decreased and the CGRP content in abdominal aorta and hypothalamus increased in SHR. By gel filtration, it showed that only one major molecular form of CGRP was present in the tissues. The CGRP specific binding sites were present both in SHR and WKY hearts, but the number of CGRP binding sites in SHR heart was higher and the binding affinity lower than those in WKY heart. Besides, CGRP can reduce the mean arterial pressure (MAP) in the SHR in a dose-dependent way. The above data indicated that CGRP may play an important role in the pathogenesis of hypertension and exert possibly a therapeutic effect on hypertension.

Animals↗
PubMed1989

[The distribution, characteristics and effects of ir-BNP in central and peripheral tissues in rat].

The present study first investigated the distribution, biochemical characteristics, receptor binding and biological effects of immunoreactive brain natriuretic peptide (ir-BNP), in the central nervous system and some peripheral tissues in rats, using highly specific radioimmunoassay, radioreceptor assay and immunohistochemical method. The results suggest that BNP may be a novel neurotransmitter or circulatory hormone, which is widely distributed in various tissues and involved in the regulation of water electrolyte balance and cardiovascular activity.

Animals↗
PubMed1988

Opioids modulate human neutrophil and lymphocyte function: thermal injury alters plasma beta-endorphin levels.

To investigate the role of opioids in the acquired immune dysfunctional state that occurs after burns or trauma, plasma beta-endorphin levels were measured serially in nine severely burned patients, and the effect of four different opioids on normal neutrophil and lymphocyte function was quantitated. The rationale for these studies is that the neuroendocrine system appears capable of interacting with and modulating immune function. The plasma levels of beta-endorphin increased to higher than normal during the first 36 hours after burn (15 versus 3.4 pmol/L, p less than 0.05) but quickly returned toward normal. Morphine had the most profound effect on in vitro neutrophil function; it decreased neutrophil chemotaxis but increased neutrophil bactericidal activity for Staphylococcus aureus, as well as resting and zymosan-stimulated oxygen consumption. Other opioids (naloxone, met-enkephalin, and beta-endorphin) had no direct effect on neutrophil chemotaxis or bactericidal activity. Both naloxone and met-enkephalin increased neutrophil oxygen consumption in a dose-dependent fashion, whereas beta-endorphin impaired neutrophil oxygen consumption. None of the opioids altered resting lymphocyte blastogenesis. The only opioid that impaired the ability of normal lymphocytes to respond to mitogen stimulation at physiologically relevant doses was beta-endorphin. These results, documenting that beta-endorphin levels are altered after thermal injury and that opioids can modulate normal neutrophil and lymphocyte function in vitro, support the concept that changes in neuroendocrine activity may occur and potentially alter immune function.

Blood Bactericidal Activity↗
PubMed1987

Anatomical analysis of the cause of skin necrosis of the great toe after transplantation of the great toe nail flap.

Necrosis of skin on the medial side of the great toe has been a significant complication of the great toe nail flap. To investigate the reason for this, a study of the blood supply of the medial side of the great toe was carried out on 55 feet with the injection of red latex into the arteries and on 13 vascular cast specimens. It was found that, after the blood vessels from the plantar and dorsal sides of the great toe are severed during the operation, the skin of the medial side of the great toe is mainly supplied by the medial vascular network at the head of the first metatarsal bone. It is clear that the blood supply from this network may sometimes be insufficient to nourish the skin. It is suggested that the operative incision should be changed so as to increase the blood supply to the medial vascular network which may decrease the incidence of skin necrosis.

Humans↗