PubMed Health⌕ Search

Biomedical subjects

X Z Yu

Publications and source records attributed to X Z Yu.

34 records · Page 2Linked to original sources
PubMed1994

Influence of in vitro methods, receptor fluids on percutaneous absorption and validation of a novel in vitro method.

In vitro experiment using excised skin has been valuable for studying the mechanism of percutaneous absorption. Based on previously established static diffusion cell system in this laboratory, a novel model-perfused glass diffusion cell system is designed. The results of initial comparative study on percutaneous absorption between glass perfused diffusion cell and static diffusion cell, in vitro and in vivo permeation as well as factors affecting permeation with seven radiolabelled chemicals are presented. The results demonstrate that the perfused diffusion cell system, which used a perfusion fluid below the surface of skin to take up the materials which penetrated the skin, is more similar to physiologic condition, convenient and automatic than that of the static cell. It well predicts the in vivo percutaneous absorption if appropriate receptor fluid is chosen. The results also show that the selection of receptor fluid is critical for in vitro permeation of chemicals with different solubility.

Animals↗
PubMed1993

[Biological monitoring of workers exposed to nitrofen and experimental study on its skin permeability].

Eleven packing workers in a nitrofen manufacturer were selected in a three consecutive day field study, Skin contamination, urine excretion, and air concentration of nitrofen before and after workshift were monitored with GC-ECD method. Results showed air nitrofen concentrations in the workplace were extremely high, ranging from 5.12 to 21.60 mg/m3 (TWA). The hand and forehead in workers, who handled wettable nitrofen powder with bare hands, were contaminated by nitrofen with levels of 5.80 and 1.15 micrograms/cm2, respectively. Nitrofen excretion in urine increased after workshift and reached the highest in 10 hours, with a half excretion time of 13 hours. Permeability study with a flow-through diffusion cell in vitro showed nitrofen could easily penetrate human skin in different location of the body, and the permeability in forearm skin was stronger than that in thigh, and much more than that in abdomen skin. Nitrofen amount penetrated increased greatly as the skin barrier was damaged. Both the skin and respiratory absorption could be the important routes for nitrofen uptake. It was imperative to protect the skin from contamination while to strengthen respiratory protection. Results also suggested nitrofen level in urine could be used to indicate the body uptake through different routes.

Adult↗
PubMed1993

[Observations on serum digoxin-like immunoreactive substances in patients with cor-pulmonale].

The level of endogenous digoxin-like immunoreactive substances (DLIS) was determined with RIA in 27 patients with cor-pulmonale and 10 normal subjects as controls. The results showed that the concentration of serum DLIS was 0.51 +/- 0.18 ng/ml in the controls, 0.82 +/- 0.24 (P < 0.05), 1.45 +/- 0.51 (P < 0.001), and 2.31 +/- 1.22 ng/ml (P < 0.001) in the patients groups with cardiac function grade II (9 cases), III (10 cases) and IV (8 cases) respectively. It has been reported that both endo- and exogenous digoxin-like substances have the same function. Cor-pulmonale patients with heart failure who are treated with digoxin tend to have toxic reactions. We consider the increase in serum endogenous DLIS as the cause. It is suggested that the dosage of digoxin, if it must be used, should be individualized and the serum level monitored if possible, so as to achieve best therapeutic effects with smaller doses.

Adult↗
PubMed1992

Cyanide selectively augments kainate- but not NMDA-induced release of glutamate and taurine.

The effect of cyanide on the kainate-, quisqualate- and N-methyl-D-aspartate (NMDA)-induced release of several amino acids from cerebellar granule neurons was studied. Cyanide, 100 microM, augmented the kainate- and quisqualate-induced release of glutamate and taurine in neurons but had no effect on the NMDA-induced release of these excitatory amino acids. In addition to the interaction with the above excitatory amino acids, cyanide had effects on several amino acids independent of excitatory amino acid stimulation; cyanide treatment resulted in a significant elevation over saline controls of arginine and taurine, but not alanine, aspartate+asparagine or glycine. With the exception of taurine, this pattern was not apparent in cells treated with any of the above excitatory amino acid.

Animals↗
PubMed1992

Amitriptyline prevents N-methyl-D-aspartate (NMDA)-induced toxicity, does not prevent NMDA-induced elevations of extracellular glutamate, but augments kainate-induced elevations of glutamate.

The effect of amitriptyline on kainate- and N-methyl-D-aspartate (NMDA)-induced toxicity and release of amino acids from cerebellar granule neurons was studied. The ED50 for amitriptyline, imipramine, and nortriptyline protection against NMDA-induced toxicity was 6.9, 6.5, and 1.3 microM, respectively. None of these compounds protected against kainate-induced toxicity. Even though amitriptyline was protective against NMDA-induced toxicity, it had no effect on the NMDA-induced increase in extracellular levels of glutamate or aspartate from these cells, indicating a dissociation between NMDA receptor activation (as indicated by glutamate content elevations) and NMDA-induced toxicity. However, kainate and quisqualate treatment resulted in elevations of glutamate and taurine levels that were further augmented in the presence of 25 microM amitriptyline. These findings confirm the reports of others that tricyclic antidepressants have neuroprotective effects related to the NMDA receptor and expand on these reports by showing that even though there is protection against toxicity, the NMDA receptor is nevertheless activated, suggesting an involvement of these compounds at sites removed from the receptor. Furthermore, this is the first report showing an interaction of tricyclic antidepressants with the function of non-NMDA receptors.

Amitriptyline↗
PubMed1992

[Lymphatic metastasis of breast cancer and selection of operation].

Studies of 169 cases of breast carcinoma showed that lymphatic metastasis was closely related to biological behavior of the cancer. Modified radical operation or modified extended radical operation were performed in cases of TNM stage I and II by pre- and intraoperative estimation of the tumor less than or about 5 cm in diameter, limited within mammary gland, and of expansion type. Histological typing and grading, degree of infiltration, condition of ER and lymphatic metastasis were used to plan postoperative adjuvant therapy. The importance of investigation of ER status of the lesions lies in proper arrangement of combined therapy and prediction of prognosis.

Adult↗
PubMed1992

[Preliminary report of the treatment of luteal phase defect by replenishing kidney. An analysis of 53 cases].

53 patients with Luteal phase defect (LPD) were treated with different Chinese medicinal herbs at different phases of menstrual cycle. On the 5th day of the menstrual cycle, the treatment was implemented with the rationale of "nourishing the Kidney Yin, invigorating the Spleen and replenishing the Qi, promoting the blood circulation and enriching the Blood" which might promote follicular development. The principle for the postovulatory treatment was that "invigorating the Kidney and strengthening the Yang" might enhance the development of corpus luteum and maintain its function. The patients were treated for three menstrual cycles. There were significant improvement in the luteal phase of endometrium, and prolonged basal body temperature elevation in progestational stage with a tendency for normalization of the wave forms and its amplitude after the treatment. In the mid-progestational stage, the level of serum LH and PRL were reduced (P < 0.05) and that of serum progestin (P) rose significantly (P < 0.01), as compared with those before the treatment. The findings suggested that Chinese herbal medicines capable of replenishing the Kidney could regulate the hypothalamus-pituitary-ovarian axis and thus improve the luteal function. Among the 53 cases, 22 (41.5%) conceived but 68.18% of them required other measures to preserve the pregnancy.

Adult↗
PubMed1986

Oral rehydration in China.

Oral rehydration with salt and sugar solution for diarrhea seems to have been widely used in China for more than 20 years. Surveys in five rural counties in widely distributed provinces have revealed that over 90 per cent of barefoot doctors and county doctors have been using a simple salt and sugar solution. Thirty-four per cent of mothers also said they used the oral solution. By contrast, most urban hospitals, especially teaching hospitals, continued to rely on intravenous (I-V) fluids. It had been previously observed that China has had high morbidity but low mortality from diarrheal diseases. Part of the explanation undoubtedly is the relatively good nutritional status of children and the widespread use of liquid traditional medicines. The finding that barefoot doctors have been using oral rehydration also may help explain the low mortality.

Administration, Oral↗