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Biomedical subjects

G Xu

Publications and source records attributed to G Xu.

At least 397 records · Page 22Linked to original sources
PubMed1996

Effect of macrolide antibiotics on macrophage functions.

Macrolide antibiotics have a variety of actions other than antimicrobial activities. Recently, it has been suggested that macrolide antibiotics act as immunomodulators. In this study, we evaluated the effects of macrolide antibiotics on macrophage functions. For the macrophage, we used the mouse macrophage cell line J774.1. The following effects of macrolide antibiotics on macrophage functions were evaluated: the effect of macrolide antibiotics on macrophage growth; the phagocytosis of beads; cytocidal activity against Candida albicans; and chemotaxis to lipopolysaccharide (LPS). Macrolide antibiotics except for azithromycin significantly stimulated the growth of the macrophage. In addition, pretreatment with macrolide antibiotics except for roxithromycin significantly stimulated the macrophage phagocytosis of beads, macrophage chemotaxis to LPS, and macrophage cytocidal activity against Candida albicans. These results suggest that macrolide antibiotics stimulate macrophage functions.

Animals↗
PubMed1996

Ste50p sustains mating pheromone-induced signal transduction in the yeast Saccharomyces cerevisiae.

In the yeast Saccharomyces cerevisiae, the heterotrimeric G protein transduces the mating pheromone signal from a cell-surface receptor. Free G beta gamma then activates a mitogen-activated protein (MAP) kinase cascade. STE50 has been shown to be involved in this pheromone signal-transduction pathway. In this study, we present a functional characterization of Ste50p, a protein that is required to sustain the pheromone-induced signal which leads cells to hormone-induced differentiation. Inactivation of STE50 leads to the attenuation of mating pheromone-induced signal transduction, and overexpression of STE50 intensifies the pheromone-induced signalling. By genetic analysis we have positioned the action of Ste50p downstream of the alpha-pheromone receptor (STE2), at the level of the heterotrimeric G protein, and upstream of STE5 and the kinase cascade of STE11 and STE7. In a two-hybrid assay Ste50p interacts weakly with the G protein and strongly with the MAPKKK Ste11p. The latter interaction is absent in the constitutive mutant Ste11pP279S. These data show that a new component, Ste50p, determines the extent and the duration of signal transduction by acting between the G protein and the MAP kinase complex in S. cerevisiae.

Alleles↗
PubMed1996

Removal of CO2, moisture and heat from ventilated suit under different pressures.

The relative equation among CO2 partial pressure in a helmet, ventilating flow, pressure and CO2 output, the relative equation among ventilating flow, pressure, humidity and rate of moisture removal, and the relative equation among ventilating flow, pressure, humidity and rate of heat removal were derived and analyzed. Its demonstrated that: ventilating mass flow for a constant CO2 partial pressure in the helmet decreases linearly as the pressure drops; the ventilating mass flow for removing a constant quantity of moisture decreases as pressure drops; the efficiency of heat removal increases as pressure drops due to the increase of moisture removal. The equations can be used for estimating ventilating flow in a ventilated suit and ventilating flow entering the helmet, and also for calculating automatically the quantities of moisture and heat removal by ventilation.

Carbon Dioxide↗
PubMed1996

Abnormal cholesterol biosynthesis in the Smith-Lemli-Opitz syndrome.

The Smith-Lemli-Opitz syndrome is caused by an inherited defect in 7-dehydrocholesterol-delta7-reductase, the enzyme that catalyzes the last reaction in cholesterol biosynthesis, the conversion of 7-dehydrocholesterol to cholesterol. As a result, deficient cholesterol is produced and the precursor 7-dehydrocholesterol and derivatives (8-dehydrocholesterol and 19-nor-5,7,9(10)-cholestatrien-3 beta-ol) accumulate. Tissues (especially brain) deprived of cholesterol, or because of the deposited sterol precursors and derivatives, develop abnormally and function poorly. Replacement with dietary cholesterol may help correct the biochemical defects and improve symptoms.

Adolescent↗
PubMed1996

A national study of factors influencing the career choice of osteopathic and allopathic family physicians.

This study examines the differences between osteopathic and allopathic physicians regarding those factors influencing their career choice of family practice. A total of 256 osteopathic physicians and 717 allopathic family physicians were surveyed. The surveyed physicians graduated in 1983 and 1984. Comparisons were made on 19 variables that influenced the physicians' decisions to enter family practice as well as on the six factor scores derived from these 19 variables. Osteopathic physicians' decisions to choose family practice was more influenced by financial obligations, medical school experiences, and family values, whereas the allopathic physicians were more influenced by personal social value. Overall, medical school experience and personal social value were two important factors that explained the largest variances of the 19 predictors influencing physicians' decisions to enter family practice. Those allopathic medical schools whose mission emphasizes the production of generalist physicians may be able to model some approaches already in place at osteopathic medical schools. Because of the influence of the personal social value factor in medical students' choosing family practice medicine, this factor warrants further study.

Career Choice↗
PubMed1996

[A clinical report on mixed astigmatism].

OBJECTIVE: This study was designed to analyze the common cause of asthenopia, mixed astigmatism. METHODS: The types and characters of mixed astigmatism in 356 eyes (207 patients) were analyzed and their naked and corrected visual acuities were investigated. Some problems of mixed astigmatism were discussed. RESULTS: Most of the patients had evident visual defects, the average naked visual acuity being 0.3 (20/60). However, all the patients had better corrected visual acuities with an average of 0.6 (20/30). CONCLUSIONS: Due to the presence of accommodation during the examination, an incorrect lens may be prescribed. Three mistakes might occur, (1) A mixed astigmatism is not detected, and a simple myopic lens is prescribed; (2) An eye with mixed astigmatism is diagnosed as simple or compound myopic astigmatism; (3) A hyperopic astigmatism is diagnosed as mixed astigmatism. The visual defects caused by mixed astigmatism can be satisfactorily corrected by spectacles.

Adolescent↗
PubMed1996

[Study of amount of bleeding in endoscopic sinus surgery].

The amount of bleeding and its relative factors were statistically analysed. The result showed that amount of bleeding was closely related to following factors, time of operation, type of anesthesia, pattern and duration of surgical procedure, and skill of surgeons. The non-elasticity of blood vessels in scar tissue, and abnormal vessels in hyperplastic pathologic tissue were the most important factors which induced bleeding in patients for revision surgery. In order to reduce bleeding, some devices were suggested.

Adolescent↗
PubMed1996

[Intestinal flora in renal allograft recipients].

OBJECTIVE: To explore the change of 10 kinds of intestinal flora in renal allograft recipients and its significance. METHODS: Ten kinds of intestinal flora in faeces were investigated in 30 renal allograft recipients by Kang Bai's classification of flora, and compared with 100 patients with diarrhea and 30 normal controls. RESULTS: The number of enteric bacilli in renal allograft recipients (8.5 +/- 1.0 CFU/g) was increased more markely than in the diarrhea patients (7.7 +/- 1.1 CFU/g, P < 0.01). The number of bacteroid (7.8 +/- 0.6 CFU/g), bifidobactercium (7.7 +/- 0.3 CFU/g), eubaclerium (7.2 +/- 0.6 CFU/g), and clostridium (7.8 +/- 0.5 CFU/g) in renal allograft recipients were decreased more markedly in than normal control (8.2 +/- 0.7 CFU/g, P < 0.01, 8.3 +/- 0.7 CFU/g, P < 0.01, 8.1 +/- 0.9 CFU/g, P < 0.01, 8.0 +/- 0.8 CFU/g, P < 0.01), but the number of Bifidobactercum was higher than that is the diarrhea patients (7.3 +/- 0.6 CFU/g, P < 0.01). The number of eubacterium was Lower than that in the diarrhea patients (7.7 +/- 0.8 CFU/g, P < 0.01). Among 30 renal allograft recipients 3 had constipation and 20 diarrhea. Two cases died of toxic shock with serious diarrhea because of imbalance of intestinal flora. CONCLUSION: The imbalance of intestinal flora existes in the early stage of renal transplantation. It is characterized by anaerobic bacilli imabalance such as bifidobacteriam and may be a direct cause of intestinal infection as diarrhea.

Adolescent↗
PubMed1996

[Effects of electroacupuncture at du meridian on contents of nitric oxide and endothelin in rats with acute cerebral ischemia].

Thirty rats were randomly assigned to three groups, control group (10 cases), acute cerebral ischemia group (10 cases) and electroacupuncture (EA) group (10 cases). The bilateral common carotid arteries were occluded, which caused sharp drop of regional cerebral bloodflow and led acute cerebral ischemia. Contents of nitric oxide (NO) and endothalin (ET) in the cerebral cortex and boold were determined in normal, during occluding and after EA of Du meridian (GV 20, GV 14) point in rats. It was found that in acute cerebral ischemia, the brain contents of NO and ET increased, the plasme level of ET elevated and serum level of NO decreased. After EA of Du meridian point, the levels of ET and NO in the brain and blood were returned significantly to normal. It is suggested that EA at Du meridian have protective effect on neural damage induced by brain ischemia. NO and ET are possibly involved in the regulative effect of EA.

Animals↗
PubMed1996

Preparation of monoclonal antibodies against chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase and their effects on enzyme activities.

The effects of the monoclonal antibodies (McAbs) directed against chicken liver 6-phosphofructo-2-kinase/fructose-2, 6-bisphosphatase (6PF-2-K/Fru-2, 6-P2ase) on the structure and function of the enzyme were studied. Using chicken liver 6PF-2-K/Fru-2, 6-P2ase as antigen, 7 clones of monoclonal antibodies specifically binding with the antigen were obtained. The epitopes of the antigen recognized by the 6 McAbs localized on the fructose-2, 6-bisphosphatase domain of chicken liver 6PF-2-K/Fru-2, 6-P2ase, and the other (H2) are on the 6-phosphofructo-2-kinase domain. All of the 7 McAbs could activate the kinase activity of the bifunctional enzyme by twofold and had a similar effect on the bisphosphatase activity of the bifunctional enzyme which resulted in a fourfold increase of the bisphosphatase activity of the bifunctional enzyme. However, the McAbs did not affect the activity of the separated fructose-2, 6-bisphosphatase domain. The results suggested that the Fru-2, 6-P2ases in the bifunctional enzyme and in the separated bisphosphatase domain were in two different conformation and activity states.

Animals↗
PubMed1996

[An ultrastructural pathological study of pterygium].

OBJECTIVE: To study the ultrastructural changes of pterygium. METHOD: The pathological ultrastructure of pterygium was studied by Hu-12A transmission electron microscopy in 14 specimens. RESULTS: The result indicated that normal and abnormal elastic fibers and collagenous fibers existed in the pterygium. As hyperplastic fibers intruded into the corneal subepithelium, Bowman's membrane was broken. To a certain extent, blood vessel multiplication and degeneration were found in the pterygium. One of the important factors was blood vessel multiplication and degeneration which affected the occurrence and development of pterygium. CONCLUSION: Multiplication and degeneration of elastic and collagenous fibers were the prominent pathological changes, and the pre-elastic fibers and denatured elastic fibers were the main compositions of pterygium.

Adult↗
PubMed1996

[Microsurgical treatment of cavernous sinus tumor].

We studied 25 cases of cavernous sinus tumors who underwent microsurgical operation. The tumors were mainly composed of neurinomas and meningiomas. The tumors of 8 of 9 cases of the former, and 4 of 6 cases of the latter were totally removed. None of the patients died. We discussed the operative, method, preoperative preparation and postoperative complication.

Adolescent↗
PubMed1996

[Endoscopic sinus surgery for the treatment of inverted papilloma of nasal cavity and paranasal sinuses].

Fourteen patients suffering from inverted papilloma of the nasal cavity and sinus were operated by the intranasal endoscopic approach. The period of follow-up were 24-60 months. Only one case had recurrence after three months and was then cured by a combined treatment of external nasal approach and radiotherapy. The other 13 cases had no recurrence in the follow up period. The intranasal endoscopic surgical technique was proved a better method for treating inverted papilloma of nasal cavity and sinus even when the lesions had affected the posterior ethmoid and spenoidal sinuses. It seems that this approrch would be a new way for removing inverted papilloma completely and the major advantage of which is an incision of the face can be avoided, while the curative rate might be the same or even better than that of the external approach.

Adult↗
PubMed1996

[Microscopic identification of the powder of roots of genus Adenophora. I. The roots of Sect. Basiphyllae and Sect. Pachydiscus].

This paper deals with the microscopic characteristics of the powder of the roots of Genus Adenophora. Eighteen species and subspecies have been studied. The results show that Sect. Basiphyllae and Sect. Pachydiscus can be identified easily based on the amount of sclerified cork cells, and 18 species, subspecies and varieties can be identified according to the amount, shape and thickness of the walls of the sclerified cork cells, the diameter and pit of the vessels, the number and shape of the secretion of the laticifers, and the number of inulin crystals.

Magnoliopsida↗