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Biomedical subjects

G Zhang

Publications and source records attributed to G Zhang.

At least 397 records · Page 22Linked to original sources
PubMed1998

[Detection of small alveolar bone lesions by digital subtraction radiography].

OBJECTIVE: To employ digital subtraction radiography (DSR) system developed by our school and co-ordinative unit, for diagnosis of small artificial alveolar bone lesions, in order to evaluate the system. METHODS: Seventy-two 0.2-0.9 mm3 lesions were produced in premolar and molar areas of the dry human mandibles. The reference and subsequent radiographs were taken before and after lesions being made. The small lesions were detected by conventional radiographs and by DSR method respectively. RESULTS: As for 0.2-0.5 mm3 lesions, the detections by both DSR and conventional methods were less than 50%. As for 0.7 mm3 lesions, the detection by DSR and conventional methods were 57.5% and 38.7%, respectively (P < 0.01). As for 0.9 mm3 lesions, the accuracy of the detection by DSR and conventional methods was 89.3% and 57.3% (P < 0.01). CONCLUSION: The detectability of small alveolar bone lesions by DSR system was obviously superior to the conventional method.

Alveolar Process↗
PubMed1998

[Vascular structure of malignant tumours of the mandible shown by specimen arteriography].

OBJECTIVE: To investigate the vascular structure of different kinds of malignant tumours of the mandible. METHODS: Specimen arteriography was performed on 11 cases of malignant tumours of the mandible. RESULTS: Malignant tumours could be divided into two groups: 1. the hypervascular tumours, the arteries are dilated, distributed evenly and arranged in a bush-like pattern. 2. hypovascular tumours, the scanty arteries are distributed unevenly without dilation, in some areas, the shape of arteries are irregular and arranged in a network pattern. CONCLUSION: Variation in vascular structure of malignant tumours in the mandible may be related to the outcome of regional chemotherapy.

Adolescent↗
PubMed1998

[Lung autotransplantation technique in the treatment of stage III bronchogenic carcinoma].

OBJECTIVE: To perform a double sleeve right upper and middle bilobectomy with transposing the inferior pulmonary vein to the superior one stump in a lung cancer patient. METHOD: The "cut-down" lobe was immersed in heparin solution in vitro for 15 minutes. It took 15, 14 and 10 minutes to finish the anastomosis of pulmonary vein, bronchus, and artery. The pulmonary artery was blocked for 3 hours. Postoperatively, the patient underwent ventilation for 6 hours. RESULT: In the 5th day after operation, re-implanted lung inflated well, the chest tube was retreated, and the patient can walk around. The reconstruction of pulmonary vessels and airway was done by spiral CT, which demonstrated no stenoses of bronchi and the pulmonary blood perfused and returned very well 3 weeks after operation. Follow-up more than 6 months showed the patient had a good quality of life and resumed his work. CONCLUSION: It is indicated to apply the technique of lung autotransplantation for operation on the central bronchogenic carcinoma when the main bronchus or pulmonary artery involved by tumor is too long to perform the anastomosis in the double sleeve bilobectomy.

Bronchi↗
PubMed1998

[Subpopulations of TIL in renal cell carcinoma and their clinical significance].

OBJECTIVE: To study the relationship between tumor-infiltrating lymphocytes (TIL) and the prognosis of patients with renal cell carcinoma. METHOD: Immunohistological chemistry method was employed to semiquantitatively assess the expression of TIL and its subpopulations. The prognostic values of various TIL subpopulations were also evaluated. RESULT: T-lymphocyte was the main component of TIL, B-lymphocyte, monocyte, and nature killer (NK) cells were also presented but in relatively small numbers. T-lymphocyte was strongly correlated to the survival probability, but this correlation was not observed between the host survival and TIL or other subpopulations. CONCLUSION: T-lymphocyte can represent the host immunological status and can be used to judge the prognosis of patients with renal cell carcinoma.

Adult↗
PubMed1998

[Direct vision mitral valve reconstruction: a long-term follow-up of 46 cases].

OBJECTIVE: To improve the long-term results of direct vision mitral valve reconstruction. METHOD: From July 1983 through July 1995, 46 patients with mitral valve disease were treated by a direct vision reconstructive techniques. Rheumatic valve stenosis and incompetence were noted in 39 (patients), nonrheumatic insufficiencies in 5, and congenital disease in 2. According to leaflet pliability, type I normal leaflet motion was notedin 17 patients, type II leaflet prolapse in 3 and type III restricted leaflet motion in 29. Cardiac function (NYHA classification) showed class II in 2, class in 25 III, and class IV in 19. Valvuloplasty and annuloplasty were performed with various techniques according to the pathanatomical changes of the valve. Prosthetic obturators self made were employed in 29 patients. RESULT: The operative mortality rate was 6% (3/46). In the mitral valve replacement group it was 10% (27/265). Two to 10 years (mean 65 months) follow-up showed grade I cardiac function in 6 patients, grade II in 17, grade III in 8, and grade IV in 3. CONCLUSION: Good long-term results can be achieved by valve reconstruction with lower mortality and incidence of thromboembolism than.

Adolescent↗
PubMed1998

[Effect of excitatoxicity on Ca2+/CaM PK II activity in rat hippocampal slices].

The relation between Ca2+/CaM PK II activity and excitatoxicity was studied in an in vitro model of rat hippocampal slices. The slices were exposed to 50-200 mumol.L-1 glutamate or 25-100 mumol.L-1 NMDA and glucose-free Krebs buffer for 30 min after being recovered to normal conditions by 2 hours of incubation with standard Krebs buffer. The results showed that inhibition of Ca2+/CaM PK II activity in rat hippocampal slices was induced by exogenous EAA (glutamate or NMDA), and Ca2+/CaM PK II activity values decreased to 50.1% and 44.7% of control at 200 mumol.L-1 glutamate and 100 mumol.L-1 NMDA, respectively; MK801, but not DNQX, antagonized EAA-induced inhibition of Ca2+/CaM PK II activity. When the slices were pretreated with MK801 prior to exposure to 200 mumol.L-1 glutamate or 100 mumol.L-1 NMDA, the Ca2+/Cam PK II activity values were 91.5% and 96.7%, respectively. The changes of extracellular Ca2+ or Mg2+ concentration influenced Ca2+/CaM PK II activity of the slices exposed to exogenous glutamate; Ca2+/CaM PK II activity values in the presence of extracellular Ca2+ was lower than that in the absence of extracellular Ca2+, and it changed from 50.1% of control (presence of Ca2+) to 64% of control (absence of Ca2+) at 200 mumol.L-1 glutamate, but Ca2+/CaM PK II activity values in the presence of extracellular Mg2+ was higher than that in the absence of extracellular Mg2+, and it changed from 50.1% of control(presence of Mg2+) to 36.6% of control (absence of Mg2+) at 200 mumol.L-1 glutamate. The results suggest that NMDA receptor may be involved in excitotoxicity-induced inhibition of Ca2+/CaM PK II activity.

Animals↗
PubMed1998

[Studies on the synthesis and experimental therapeutic effects of metal chlorin on 60Co-irridiated mice].

Pheophorbide a and pyropheophorbide a were prepared by acid degradation of crude chlorophylls isolated from silkworm excrement. Pheophorbide a was further degraded to chlorin e6 monomethyl ester in alkaline methanol in absence of oxygen. Pure purpurin 18 was directly prepared from alkali degradation of silkworm excrement crude chlorophylls in presence of oxygen. Nine chlorin complexes of Co, Cu and Zn were synthesized for the first time. Preliminary pharmacological tests showed that chlorin e6 monomethyl ester copper complex(7) could increase survival and prolong the surviving time of 60Co-irridiated mice significantly.

Animals↗
PubMed1998

[Researches on immunogenicity identification of recombinant Sj22.6(rSj22.6) kDa antigen gene of schistosoma japonicum].

AIM: To identify the immunogenicity and the potentiality of rSj22.6 as a candidate vaccine antigen for schistosomiasis japonica. METHODS: rSj22.6 was tested by Western blot with specific antibodies to identify its immunogenicity. The rSj22.6 protein was isolated and purified by SDS-PAGE and injected twice into rabbits to raise antirSj22.6 serum that was tested by Western blot to recognize the native protein of adult S. japonicum and SEA. C57 mice were immunized with rSj22.6 and challenged with S. japonicum cercariae to identify the protective immunity raised by rSj22.6. RESULTS: rSj22.6 could be recognized by specific antibodies and could stimulate the rabbits to produce high level of anti-rSj22.6 antibodies. Anti-rSj22.6 serum could recognize an adult native protein with the same molecular weight as rSj22.6. The preliminary immune-challenge test resulted in significant reduction in adult worm burden. CONCLUSION: rSj22.6 possesses immunogenicity in stimulating rabbits to produce high level of specific antibody and has protective role as a candidate vaccine antigen against S. japonicum infection.

Animals↗
PubMed1998

[Researches on the nucleotide sequencing of the recombinant Sj 22.6 kDa antigen gene of Schistosoma japonicum].

AIM: To sequence the cloned gene in pGSj24 and to identify the encoded protein. METHODS: The cloned gene in pGSj24 was digested from the recombinant plasmid by EcoRI, ligated into the M13mp19 vector and sequenced by automatic sequencer. The sequence was analyzed by Goldkey DNA and Protein Analytical Program and DNASIS Program. RESULTS: The pGSj24 cloned gene was demonstrated to be 840 bp containing one opened reading frame (ORF) with an initiation codon ATG at position 23 nt and a termination codon TAA at position 596 nt, encoding a protein with a molecular weight of 22.6 kDa. At the upstream and downstream of the ORF there were termination codons, so the encoded protein was unable to be larger. However, there was a termination codon TAA at position 11 nt, suggesting why the 22.6 kDa protein expressed separately. The nucleotide sequence of the pGSj24 cloned gene shared 95% identity with that of the corresponding part of S. japonicum 22.6 kDa antigen gene, and 99.7% identity in the encoding part. The deduced amino acid sequence analysis showed a sequence motif known as EF-Hand calcium binding domain, several endoplasmic reticulum targeting sequences and microbodies C-terminal targeting signals. The possible antigen determinants were predicted within the amino acid fragments of 29-32aa, 63-68aa and 87-101aa. CONCLUSIONS: The cloned gene in pGSj24 is the gene that encodes Sj22.6 kDa antigen.

Amino Acid Sequence↗
PubMed1998

[The study on detection of human parvovirus B19 DNA in spontaneous abortion tissues].

116 spontaneous abortion tissues were detected for human parvovirus B19 (HPV B19) DNA by nested polymerase chain reaction. Of the abortion tissues detected, 66 were paraffin embedded and 50 were fresh abortion tissues, At the same time, 25 abortion tissues from healthy artificial abortion women were collected as control. The results showed that 27.3% (34/116) of 116 spontaneous abortion tissues were positive for HPV B19 DNA, and only 4% (1/25) were positive in the control group, the discrepancy was significant chi 2 = 5.769(P < 0.05). It suggests that there is a relationship between spontaneous abortion and HPV B19 infection. HPV B19 infection may be an important factor in spontaneous abortion.

Abortion, Spontaneous↗
PubMed1998

[Three-dimensional volumetric display--a new application of frequency up-conversion].

This paper discusses the present research situation and the application prospect of 3-D volumetric display technology. The possible usability and science significance of frequency up-conversion in 3-D volumetric display field are also demonstrated systematically. In ZBLAN: Pr, Yb glasses, we primarily demonstrated and achieved a new application of frequency up-conversion three dimensional volumetric display, using the two-frequency up-conversion of the rare earth ions. The efficiency of luminescence of Pr was enhanced much by the energy transfer between Pr and Yb ions.

English Abstract↗
PubMed1998

[Studies on the oxidation reaction of octanol-2 with nitric acid by infrared spectroscopy].

In this paper, the reaction process of oxidation of octanol-2 with nitric acid has been studied by IR spectroscopy. It is found that the main components of non-sapoifiable matter are different in different oxidation degrees. The relation between oxidation products and the amount of nitric acid are investigated,the reaction mechanism has also been studied. Experimental results show that the oxidation process of octanol-2 is as follows: first, octanol-2 is oxidated to octanone-2, or to nitrate, nitrite and nitrile copmpounds, then these compounds are reoxidated to caproic acid in the meantime some by-products, such as valeric, enanthic acids are also found in oxidated products.

English Abstract↗
PubMed1998

[Spectra analysis of ignition flame in two-stroke gasoline engine burning blended fuel].

In a two-stroke gasoline engine, exhaust gas pollution is especially severe when it burns rich mixture of blended fuel. The results of spectra analysis of ignition combustion flame show that the peak luminous intensities of three characteristic spectra CH(431.5nm), C2(516.5nm) and CN(387nm) are strong, of which the peak luminous intensity of CN(387nm) is the most outstanding. The mechanism of NO(x) formation in exhaust gas can be illustrated by Fenimore theorem. The mechanism was also verified by experiments conducted by Japanese researcher K. Nagase.

English Abstract↗
PubMed1998

[Indirect sensitized upconversion in Tm3+ and Yb3+ codoped non-crystal pentaphosphate].

We report the blue upconversion luminescence of Tm3+ and Yb3+ codoped non-crystal pentaphosphate pumped by -798nm laser diode. The samples were directly excited to 3F4 level of Tm3+ ion. Two energy transfer processes between Tm3+ and Yb3+ contribute mainly to the population of 1G4 level of Tm3+. Phonon plays an important role in the upconversion process.

English Abstract↗
PubMed1998

Parallel comparative trial of amlodipine and nitrendipine monotherapy in patients with essential hypertension.

OBJECTIVES: To compare the blood pressure effects of two dihydropyridine calcium channel blockers, amlodipine and nitrendipine, in 488 patients with essential hypertension. METHODS: The study used a randomized, single-blind design of 4 weeks' duration conducted at four medical centres in China. Patients were randomized to receive either amlodipine monotherapy (5-10 mg once daily; n = 334) or nitrendipine (10 mg twice or three times daily; n = 1 54). Blood pressure was evaluated by standard blood pressure measurements before and after treatment, and by 24 h ambulatory blood pressure monitoring in a subgroup of patients (n = 18). RESULTS: Both systolic and diastolic blood pressures were reduced from baseline after 4 weeks of amlodipine and nitrendipine monotherapy. Diastolic blood pressure was reduced by 14.4% in the amlodipine group, which was significantly better than the 13.0% reduction in the nitrendipine group (P< 0.05). In addition, blood pressure response rates were significantly better with amlodipine monotherapy than with nitrendipine monotherapy. In the subgroup of patients undergoing 24 h ambulatory blood pressure monitoring, both systolic and diastolic blood pressure were reduced from baseline in the amlodipine and nitrendipine groups. Adverse effects were generally mild, with dizziness, flushing, palpitation, headache, drowsiness and ankle oedema being the most common. Rushing and headache were more frequent in the nitrendipine group than in the amlodipine group (P< 0.05 for flushing and P<0.01 for headache). CONCLUSIONS: Amlodipine monotherapy reduced blood pressure more effectively than nitrendipine monotherapy in patients with essential hypertension and was associated with fewer adverse events.

Adult↗
PubMed1998

An apolipoprotein E synthetic peptide selectively modulates the transcription of the gene for rat ovarian theca and interstitial cell P450 17alpha-hydroxylase, C17-20 lyase.

Ovarian theca/interstitial cells produce androgens in response to luteinizing hormone (LH) stimulation and apolipoprotein (apo) E exerts a selective effect on the type of steroid product made by these cells. We have identified an apoE synthetic peptide containing the low density lipoprotein (LDL) receptor binding domain, acetyl-Y(LRK LRKRLLRDADDL)2C, that mimics the activity of native apoE. Depending on the concentration, the apoE synthetic peptide either enhanced or inhibited the LH-stimulated production of androstenedione with concomitant changes in the mRNA for its synthetic enzyme, P450 17alpha-hydroxylase, C17-20 lyase, without any changes in progesterone production or the mRNA for its synthetic enzyme, P450 cholesterol side-chain cleavage. The apoE synthetic peptide caused changes in the rate of transcription of the mRNA for P450 17alpha-hydroxylase, C17-20 lyase without altering its stability. Pretreatment of the theca/interstitial cells with receptor-associated protein, which blocks apoE binding to members of the LDL receptor superfamily, prevented the apoE synthetic peptide-mediated stimulation of androstenedione and mRNA for P450 17alpha-hydroxylase, C17-20 lyase, but did not attenuate the inhibitory activity of the peptide. Thus, apolipoprotein E selectively altered the type of steroid made by ovarian theca/interstitial cells by regulating the transcription of mRNA for the gene for P450 17alpha-hydroxylase, C17-20 lyase, in part through its interaction with apolipoprotein E-specific receptors of the LDL receptor superfamily.

Amino Acid Sequence↗
PubMed1997

HIV-1 infection in women is associated with severe nutritional deficiencies.

Nutritional deficiencies may contribute to immune dysregulation, and have been shown to be sensitive markers of HIV-1 disease progression. Only limited information exists, however, regarding the nutritional profile of HIV-1-seropositive drug abusers. Immune and nutritional measurements were obtained in a subsample of 125 subjects from a larger cohort of drug users being followed for HIV-1 infection and cofactors of disease progression. Nutritional deficiencies, particularly vitamins A, E, and zinc, were widespread with up to 86% of the drug users exhibiting at least one nutritional alteration. Although immune parameters (CD4 count, CD8 count, beta2-microglobulin) were similar in the HIV-1-infected men and women, women had significantly poorer overall nutritional status, as measured by plasma proteins, which are considered to be sensitive markers of malnutrition. A comparison of individuals with advanced disease (CD4 count <200/mm3) revealed significantly lower levels of plasma prealbumin (p < .01), selenium, (p < .05), and greater deficiency of vitamins A (p < .01) and E (p < .05) in women than in men. The greater severity of nutritional deficiencies noted in HIV-1-infected women may be an important determinant of disease progression and survival.

Adult↗