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Biomedical subjects

D Cheng

Publications and source records attributed to D Cheng.

At least 109 records · Page 6Linked to original sources

[The identification of banding chromosomes by computer image analysis].

The analysis system for banding chromosomes (SYSTEM), an image analysis software, was programmed. By the SYSTEM the photos of Chinese G banding chromosomes were analyzed. It showed that the karyotype of the chromosomes of persons was recorded in high speed and efficiency, and that the chromosomes of alike ordinal number from different persons could be compared directly. That would presage, by this kind of the high effective operation, a favorable condition was created for the application of the polymorphism of the chromosomes to the parentage diagnosis.

Chromosome Banding↗

[Diagnostic value of pleuro-examination with fiberoptic bronchoscope in indefinite pleural effusions].

The diagnostic value of pleuro-examination with fiberoptic bronchoscope in indefinite pleural effusions was studied. Pleuro-examination with fiberoptic bronchoscope has been performed in 10 cases with indefinite pleural effusions, and its diagnostic value and complications have been observed. The results showed that the diagnoses were confirmed in 9 of 10 patients submitted to pleuro-examination, and no severe complications were found. The results suggest that pleuro-examination with fiberoptic bronchoscope is an effective and safe procedure and might be performed on patients with pleural effusions when routine examinations fail to provide a diagnosis.

Adenocarcinoma↗

[The value of erythromycin pleurodesis in the treatment of malignant pleural effusions].

Malignant pleural effusion is a frequent complication of patients with advanced malignant tumors. For many patients suffering from malignant pleural effusion that increases rapidly and may be life threatening, it is important to control the effusions. To investigate the value of erythromycin as a pleural sclerosant, a dose of 1 g erythromycin in 30 ml of 5% glucose was injected into the pleural cavity of 26 patients with malignant pleural effusion. The results were assessed by Miller's standards. After treatment, numerous adhesions were present in 15 cases; Pleural effusion reduced in 7 patients, and no effect was noted in 4 patients. The total response rate was 84.6%, and there were no severe side-effects. The erythromycin-induced pleurodesis is probably the result of induced chemical inflammation in the locality. This study suggests that erythromycin is a useful pleural sclerosant.

Adenocarcinoma↗

[Effect of different hypoxic duration on changes of pulmonary circulation].

In order to assess the relationship between the hypoxic duration and pulmonary hypertension, we investigated the pulmonary hemodynamics and right ventricular hypertrophy and pulmonary vascular structure changes in rats with hypoxic exposure for 1 day to 3 weeks. After hypoxic treatment, the pulmonary artery pressure of rats increased in 3 days, and it was up to peak at 2 weeks later. The weight of right ventricle of rats significantly increased after 1 week. The endothelium of pulmonary vascular of rats became swollen in 3 days, and then increased in extracellular matrix deposition. Vessel wall thickening was found in 1 week hypoxic rats, and it was very significant in 3 week hypoxic rats. The results suggest that the duration of hypoxic treatment is related to the change of pulmonary circulation in 3 weeks in rats.

Animals↗

[Study on conversion degree of double bonds of dental composites by Fourier transform infrared spectroscope].

Conversion degrees (CDs) of double bonds of 8 dental composites were measured by Fourier transform infrared spectroscope. Also, effects of disc-sampling method and film-sampling method on CD were compared. The results showed that CDs of 8 composites ranged from 45% to 75%. CDs of visible-light-cured (VLC) composites were higher than those of chemically-cured (CC) ones. In VLC composites, those with hybrid fillers had higher CDs than those with superfine fillers. In VLC composites, CDs obtained by disc-sampling method were higher than by film-sampling method; in CC composites, there were no differences between CDs obtained by both sampling methods.

Composite Resins↗

The construction and expression of deletion mutant of human pro-urokinase cDNA.

The human pro-urokinase mutant deleting 150-156 amino acids was constructed by overlap-extension PCR and other molecular cloning techniques. The mutant was expressed transiently in COS-7 cells and constitutively in CHO cells; the expression level is 450-500 IU/10(6) cells/24 h. SDS-PAGE and Western blotting analysis showed that the molecular weight of the expression product is 54 kDa, which is similar to that of the mature pro-UK and recombinant pro-UK (rPro-UK) expressed by full-length cDNA. Most of the products exist in the form of single chain; the percentage of single chain is much higher than that of rPro-UK. In addition, the mutant product is more resistant to proteinases and its affinity to fibrin is also improved slightly.

Animals↗

[TGF-beta 1 gene expression in the healing process of skin wound in rat].

For observation of the change of transforming growth factor-beta 1 (TGF-beta 1) gene expression in the process of skin wound healing, the following experiments were performed. Sixteen Wistar rats were chosen. At each side of the rat's back, a 1 cm x 1.5 cm middle-thick skin wound was made. After 3, 6, 9 and 12 days, the specimens were taken from the wounds. For each specimen, half of it was used for RNA extraction, and underwent dot blotting; and the other half was frozen immediately and underwent in situ hybridization. The probes were dig-labeled PDGF-BB cDNA probe and TGF-beta 1 probe. The results showed that TGF-beta 1 gene was expressed mainly in fibroblast, epithelial cell and capillary endothelial cell. The peak of TGF-beta 1 mRNA content was in the 6th day postoperatively. After that, the content of TGF-beta 1 decreased to normal. It was suggested that TGF-beta 1 gene expression was in close relation with healing process. TGF-beta 1 may play an important regulatory role in the skin wound healing.

Animals↗

[The effect of different way of using FGF on wound healing].

To investigate the best way of using fibroblast growth factor (FGF) in wound healing, the following experiments were performed. Twelve Wistar rats were chosen. Four 1.5 cm x 1.5 cm middle-thick skin wounds were made in the back of each rat, 2 in each side, and labelled as number 1 to 4. Number 1 wound of each rat was used as control, only PBS was applied to the wound, 50 microliters per time, twice a day from the first day to 11th day. Number 2 wound was sustained medication group, 50 microliters 4 micrograms/ml FGF was applied twice a day from the first day to 11th day; Number 3 wound was early medication group, 50 microliters 8 micrograms/ml FGF was applied twice a day from the first day to 5th day; Number 4 wound was late medication group, 50 microliters 8 micrograms/ml FGF was added twice a day from the 5th day to 11th day. By day 4, 8, 12 and 16, the area of wounds were measured, and the healing time of each wound was recorded. The elastic fiber, collagen fiber and DNA content were measured by immunohistological method. The result showed that the elastic fiber, collagen fiber and DNA content in the groups of FGF used were more than those in the control group. The healing time of the control group was 14.4 days while that of the early meduation group was 13.4 days, late medation group was 13.5 days and sustained medication group was 12.2 days. It was suggested that FGF could accelerate the wound healing, and sustained use of FGF was the best way of giving the drug.

Animals↗

[The problems in the use of superficial cervical artery skin flap and it's relevant solution].

Superficial cervical artery skin flap is widely used in clinical practice. In order to inprove the outcome of the flap in clinic, eleven cases of skin defect of scalp who were treated with the flap was discussed. After operation, the donor area healed but there was no hair growth on recipient area. Among them, six cases occurred partial necrosis of skin flaps. In order to avoid these problen, the relevant solution discussed as follows: 1. Handle well the pedicle of the skin flap to prevent the interference with venous returm. 2. Adhere strictly to indications. 3. Apply skin expander to obtain "extra" skin, then carryout the tranfer of skin flap and 4. Better use the skin flap with residual hair.

Adult↗

Expression of recombinant alpha Ains-crystallin and not alpha A-crystallin inhibits bacterial growth.

alpha A-Crystallin and alpha Ains-crystallin are derived from the alpha A-crystallin gene via alternative splicing. They are identical except for the presence of a polypeptide, 23 amino acids long, encoded by the 'insert' exon. Evolutionary logic would suggest that the insertion of a 23 amino acid peptide in the middle of alpha A-crystallin, a protein evolving more slowly than either histone H1, cytochrome c or hemoglobin, would lead to appreciable structural and functional changes. However, based on physico-chemical studies, it is presently believed that alpha A-crystallin and alpha Ains-crystallin are functionally equivalent and that the presence of the 'insert' peptide in alpha Ains-crystallin is inconsequential. We report here that the independent expression of recombinant alpha Ains-crystallin, and not alpha A-crystallin, inhibits growth of the bacterial host. These observations were confirmed in coexpression experiments, wherein both the proteins were expressed in the same cell. Interestingly, growth inhibition is reversible. Importantly, the data demonstrate that it is catalytic amounts and not the gross accumulation of alpha Ains-crystallin which causes growth inhibition. Given the prior knowledge that alpha A-crystallin and alpha Ains-crystallin differ by a peptide of 23 amino acids, these data suggest that the "insert peptide' in alpha Ains-crystallin imparts properties on this protein that are different from alpha A-crystallin.

Animals↗

Split fractures of the lateral tibial plateau: evaluation of three fixation methods.

A laboratory study was performed to compare the stability and ultimate strength of three standard fixation techniques for split-type lateral tibial plateau fractures. The three methods of fixation were (a) three 6.5-mm cancellous lag screws with washers; (b) two 6.5-mm cancellous lag screws with washers and an additional antiglide 4.5-mm cortical screw with washer; and (c) six-hole L-shaped buttress plate. Twelve pairs of embalmed mildly osteopenic lower extremities were used. Simulated split-type lateral tibial plateau fractures were created, reduced, and then instrumented in a matched pair design. The instrumented specimens were axially loaded to determine resistance to displacement, cyclically loaded to 10,000 cycles to determine dynamic stability, and then loaded to failure. There were no statistically significant differences found between resistance to displacement or failure strength as a function of either fragment size or sample bone density. On the basis of biomechanical stability, there appears to be no difference between the three fixation techniques tested. The results of this study suggest that use of an antiglide screw or buttress plate does not offer an advantage over lag screw fixation alone for the treatment of split type lateral tibial plateau fractures.

Biomechanical Phenomena↗

Preconception health care for the primary care practitioner.

There will always be birth defects and pregnancy complications due to factors beyond our control. However, we are rapidly discovering many interventions women can use to optimize their chances of having a healthy pregnancy and baby. Most of these, such as immunization and normalization of a diabetic woman's glycosylated hemoglobin level, are most effective when begun before conception. Since the discovery of the congenital rubella syndrome in 1941, there has been a steady accumulation of information on the prevention of birth defects through preconception health. In just the last few years, we have learned that folic acid can decrease neural tube defects, angiotensin converting enzyme inhibitors are teratogenic, and zidovudine can decrease the vertical transmission rate of human immunodeficiency virus. The Varivax vaccine released last year is expected to decrease the perinatal morbidity from varicella. By using the time before conception, we may be able to fully maximize the benefits of good nutrition, exercise, medical screening, and avoidance of environmental toxins.

Female↗

[Protective and treated effects of L-arginine on hypoxia-induced pulmonary hypertension in rats].

The protective and treated effects of L-Arginine on isobaric hypoxia-induced pulmonary hypertension were studied in rats. It was found that L-Arginine significantly inhibits hypoxic pulmonary hypertension and right ventricular hypertrophy. The mean pulmonary arterial pressure (mPAP) was 3.58 +/- 0.06 kPa and right ventricle/(left ventricle plus septum) ratio [RV/(LV+S)] was 0.34 +/- 0.01 in rats exposed to hypoxia (FiO2 = 0.10 +/- 0.05) for 3 weeks. The mPAP was 2.61 +/- 0.09 kPa and RV/(LV+S) was 0.26 +/- 0.01 in rats pretreated with L-Arginine [200mg/(kg.d)]i there is significant difference between the two groups. We also found that L-Arginine (300mg/kg) can decrease mPAP in rats with hypoxic pulmonary hypertension. The results suggest that L-Arginine might have significant protential for protection and treatment of hypoxic pulmonary hypertension.

Animals↗

Effects of ginkgolide B on isobaric hypoxic pulmonary hypertension in rats.

OBJECTIVE: To evaluate the effects of Ginkgolide B, a specific platelet activating factor (PAF) antagonist, on hypoxia-induced pulmonary hypertension and pulmonary vascular remodeling. MATERIALS AND METHODS: Forty male Wistar rats were divided into 4 groups, receiving normal saline, Ginkgolide B, isobaric hypoxia and isobaric hypoxia plus Ginkgolide B respectively. Pulmonary hemodynamics were assessed via right heart catheterization. Pulmonary vascular remodeling were examined by a computerized image analyser. RESULTS: Chronic hypoxia (FiO2 = 0.10, 3 weeks) caused pulmonary hypertension, pulmonary vascular remodeling and right ventricular hypertrophy in rats. Treatment with Ginkgolide B reduced the extent of pulmonary hypertension, pulmonary vascular remodeling and right ventricular hypertrophy induced by hypoxic exposure. CONCLUSIONS: The results suggest that PAF participates in the process of chronic hypoxic pulmonary hypertension and pulmonary vascular remodeling, and PAF antagonist could be a potentially useful agent for preventing hypoxic pulmonary hypertension.

Animals↗

[Effects of ginkgo plus on hypoxic pulmonary hypertension in rats].

We examined the effects of Ginkgo Plus on the pulmonary hemodynamics and right ventricular hypertrophy in rats exposed to isobaric chronic hypoxia. The rats treated with chronic hypoxia developed pulmonary hypertension and right ventricular hypertrophy. Ginkgo Plus reduced significantly the hypoxia-induced increase of mean pulmonary arterial pressure and pulmonary vascular resistance as well as the ratio of right ventricular weight vs left ventricular plus septal weights. The results suggested that Ginkgo Plus could relieve the hypoxic pulmonary hypertension.

Animals↗

[The level of platelet activating factor in blood of rats with hypoxic pulmonary hypertension].

Because hypoxia is a known predisposing factor for pulmonary hypertension, we investigated the effects of hypoxia and platelet activating factor (PAF) on the development of pulmonary hypertension in rats. Male Wistar rats were made hypoxic by placing them in a isobaric hypoxic chambar (O2 = 10%) for 3 weeks; the rats developed pulmonary hypertension and right ventricular hypertrophy. We found that PAF level in blood of rats were significantly elevated at 2-3 weeks of hypoxia (280.8 +/- 119.7 ng/ml and 324.2 +/- 67.6 ng/ml vs 148.3 +/- 60.2 ng/ml). Therefore, we conclude that PAF plays a central role in mediating hypoxia-induced pulmonary hypertension.

Animals↗

[The role of platelet activating factor in chronic pulmonary hypertension].

To investigate the chronic effects of platelet activating factor (PAF) on pulmonary circulation, we administered PAF to 15 male Wistar rats in low doses by intraperitoneal injection for 28 days. The results showed that after PAF treatment the mean pulmonary arterial pressure increased by 1.17 kPa, the pulmonary vascular resistance increased by 2409.3 kPa.s/L, the cardiac output decreased by 9.1 ml/min and the ratio of right ventricular weight to left ventricular plus septal weights increased by 0.1, compared with control. Histologic sections of the lungs were examined under light microscope equipped with a computerized image analyser. The wall of pulmonary arterioles was thickened; the percent of vascular wall thickness/vascular external diameter and percent of vascular wall area/total vascular area were increased in the PAF group (P < 0.05). These suggest that PAF may play an important role in the pathogenesis of chronic pulmonary hypertension.

Animals↗