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Biomedical subjects

Z Liu

Publications and source records attributed to Z Liu.

At least 757 records · Page 42Linked to original sources
PubMed1998

Protein expression both in mammalian cell lines and in yeast Pichia pastoris using a single expression plasmid.

We have designed and constructed a novel expression vector capable of producing recombinant proteins in both mammalian cell lines and the yeast strain Pichia pastoris. In this vector, a yeast promoter is placed inside an intron of the mammalian transcription unit. A yeast transcription termination sequence is placed immediately downstream of the mammalian polyadenylation site. In mammalian cells, transcription is driven by a mammalian promoter. The yeast promoter within the intron is removed by RNA processing. However, protein expression in yeast cells can be achieved utilizing the yeast promoter immediately upstream of the 3' splice site and the target genes. Our data indicate that this vector can express beta-galactosidase efficiently in both mammalian cell lines and the yeast strain P. pastoris.

Animals↗
PubMed1998

Genetic evaluation for herd life in Canada.

Methods were developed for the national genetic evaluation of herd life for Canadian Holstein sires. The genetic evaluations incorporate information from survival (direct herd life) and information from conformation traits that are related to herd life (indirect herd life) after adjustment for production in first lactation to remove the effect of culling for production. Direct genetic evaluations for herd life were based on survival in each of the first three lactations, which was analyzed using a multiple-trait animal model. Sire evaluations thus obtained for survival in each of the first three lactations were combined based on their economic weights into an overall sire evaluation for direct herd life. Sire evaluations for indirect herd life were based on an index of sire evaluations for mammary system, feet and legs, rump, and capacity. A multiple-trait sire model based on multiple-trait across country evaluation methodology was used to combine direct and indirect genetic evaluations for herd life into an overall genetic evaluation for herd life. Sire evaluations for herd life were expressed in estimated transmitting ability as the number of lactations and represent expected differences among daughters in functional herd life (number of lactations); the average functional herd life was set equal to three lactations. Estimated transmitting abilities were normally distributed and ranged from 2.31 to 3.43 lactations.

Animals↗
PubMed1998

Bull sperm motility and membrane integrity in media varying in osmolality.

Studies were designed to evaluate bull sperm motility and membrane integrity following exposure to Tyrode's solution varying in osmolality from 100 to 1537 mOsm. Congo red and bisbenzimide (HOECHST 33258) stains were used to distinguish between sperm with intact versus disrupted plasma membranes. Sperm motility was subjectively evaluated. No significant differences were found between motile and unstained sperm (sperm with intact membranes) in solutions with nearly physiologic osmolalities between 200 and 300 mOsm. However, in 100- and 150-mOsm solutions, the percentage of motile sperm (5 and 19%), respectively) was lower than the percentage of sperm unstained with Congo red (18 and 35%). With HOECHST 33258 stain, the corresponding values were 7 and 14% versus 26 and 31%. The percentage of motile sperm declined greatly in the 500-mOsm medium, but the proportion of unstained sperm was affected little until the osmotic pressure exceeded 732 mOsm. Partial recovery of motility occurred when sperm were returned to the isotonic medium. This study indicated that the sperm plasma membrane was more resistant to osmotic damage than were the mechanisms responsible for sperm motility. Lack of motility in hypertonic media was not an absolute indicator of cell death, and unstained sperm overestimated sperm viability, which are factors to consider when sperm are being evaluated, especially relative to cryopreservation.

Animals↗
PubMed1998

CT-guided stereotactic biopsy of deep brain lesions: report of 310 cases.

OBJECTIVE: To evaluate the accuracy of CT-guided stereotactic biopsy in making correct pathological diagnosis and choosing corresponding management of brain tumors. METHODS: From 1991 to 1995, CT-guided stereotactic biopsy was performed in 310 patients with intracerebral lesions which were deep-seated or located in certain main functional areas. The patients were 198 men and 112 women. Their ages ranged from 4.5 to 70 years (average: 39.3 years). The lesions were located in the deep cerebrum (74 patients), the sellar area (62), the basal ganglion (51), the posterior part of the third ventricle (38), other intraventricleular area (21), the cerebellum (17) and the brain stem (9), and intracranial multiple lesions were found in 38 patients. RESULTS: Brain tumors were diagnosed pathologically in 266 patients (85.8%); inflammatory process in 25 (8.1%), other lesions in 8 (2.6%) and uncertain cases were 11 (3.6%). The overall positive rate of biopsy was 96.4% and the positive rate for brain tumor was 85.8%. Intracranial hematomas after biopsy were found in 5 patients (1.6%). There were no deaths induced by the biopsy or other serious complications. CONCLUSIONS: The results suggest that CT-guided stereotactic biopsy is a reliable method for histopathological diagnosis of brain tumors and it is also of great help in selecting appropriate management.

Adolescent↗
PubMed1998

[McKay operation in the correction of rigid clubfoot].

For the evaluation of the result from McKay operation in the correction of rigid clubfoot, 71 patients (103 feet) were followed up postoperatively for 2 to 9 years. According to the criteria concerning the functional recovery of the foot, the external appearance of the foot after correction and the roentgenographic findings, the result was evaluated as excellent in 55 patients (78 feet), good in 11 patients (16 feet), fair in 5 patients (9 feet) and with no recurrence. It was considered that the favorable time for operation was when the child being 6 to 18 months old. In 7 patients (12 feet), there were morphological changes of the calcaneal and navicular bones in 12 feet, limitation of ankle movement in 9 patients and resultant flatfoot deformity in 5 patients (7 feet). The factors influencing the functional recovery of the foot and the relationship between the corrective result and the age of patient when the operation being given were discussed in details.

Child↗
PubMed1998

[Preliminary report of xenogenic bone graft for sixty-five cases].

From January 1984 to November 1997, the boiling xenogenic bone (porcine and bovine bone) was applied in 65 patients. The xenogenic bone was used to promote bone healing in 24 cases, intramedullary bone graft in 37 and osteomyelitis in 4. All of the patients were followed up for 2 to 35 months. The results showed that in five cases there was infection after operation, and all other the wounds had primary healing. The xenogenic bone seemed to induce rejection in vivo. In the sevious cases immunosuppressive treatment was often needed. The volume of the bone grafted and the extent of the periosteum being stripped seemed to be important whether xenogenic bone graft would be successful or. There were lots of problem needed investigation.

Adolescent↗
PubMed1998

Application of acupuncture and moxibustion for keeping shape.

On the basis of TCM diferentiation, the authors have treated 359 adult female cases of non-obesity with undesirable body shape by combined application of body acupuncture and moxibustion and auricular acupuncture, and achieved quite good remoulding and orthopedic results, suggesting that acupuncture and moxibustion can very effectively regulate the somatotypic indexes of body weight, circumference of the chest, loin, hip and thigh, the ratio of the loin to hip, sebum thickness, obesity degree, body mass index and body fat percentage of the cases in the overweight group and orthopedic groups 1, 2. It is therefore concluded that acupuncture and moxibustion is a good therapy for obtaining a graceful body shape.

Acupuncture Therapy↗
PubMed1998

[Microtubule-associated protein30 (MAP30) and ubiquitin detected in neurofibrillary tangles of Alzheimer's disease brains].

Using immunohistochemical technique, the distribution of immunoreactive products of antiubiquitin and MAP30 in the neurons of hippocampus of Alzheimer's disease (AD) brain were studied. Nurofibrillary tangles (NFT), dystrophic neurites in plaques and neuropil threads were labeled by the antibody of ubiquitin. NFT and pretangle neurons (PTN) were stained by the antibody of MAP30, but not detectable signal in axons or distal dendrites. The neurons immunostained with antibodies to ubiquitin and MAP30 were found in all the areas of CA1, CA2, CA3 and CA4 of hippocampus of AD. These neurons labeled by 2 antibodies used in this study were distributed more in the CA1 and CA2 than those in CA3 and CA4. The results indicate that ubiquitin is seen associated when NFT is already formed, and MAP30 may be a novel antigenic component of NFT in Alzheimer's disease.

Aged↗
PubMed1998

[The morphometric study of endometrial spiral arterioles before and after insertion of gamma CuI and TCu 220C intrauterine devices].

OBJECTIVE: To investigate the morphologic changes of endometrial spiral arterioles and its relationship with bleeding pattern after insertion of gamma-shape copper indomethacin-medicated (gamma CuI) and T-shape copper (TCu 220C) intrauterine devices (IUD). METHODS: Endometrium specimens of late secretory phase were obtained from fertile age women: 10 from preinsertion, 10 obtained after insertion of TCu 220C IUD, and 9 obtained after insertion of gamma CuI IUD. Samples were sectioned serially and morphometric analysis of endometrial spiral arterioles was performed under light microscope. RESULTS: The average cross section area (Area), maximum diameter (Dmax) and minimum diameter (Dmin) of spiral arterioles in both spongeous and dense layers of endometrium increased significantly after insertion of TCu 220C IUD. After insertion of gamma CuI IUD, the Area and Dmax increased in dense layer only, though less obviously than that occurred in TCu 220C group. However, the Dmin increased more obviously in both spongeous and dense layers than after insertion of TCu 220C IUD, implying that the shape of spiral arterioles was more regular in gamma CuI group. CONCLUSION: gamma CuI IUD has less effects on the morphological changes of endometrial spiral arterioles, and this may relate to its indomethacin-contained which causes less bleeding.

Adult↗
PubMed1998

[Effects of plasma endothelin-1 and aldosterone on sodium retention in children with nephrotic syndrome].

The effects of plasma endothelin-1 (ET-1) and aldosterone (Ald) on sodium retention in children with nephrotic syndrome were investigated. 14 cases were divided into the edematous stage and non-edematous stage. Plasma ET-1, Ald, and serum osmolarity, albumin (Alb), and Na+ were measured in each stage. The results showed that the plasma ET-1 in edemaous stage increased significantly, compared with that in no-edematous stage (P < 0.01). There was no significant difference in plasma Ald between the edematous stage and the non-edematous stage. Plasma ET-1 was positively correlated with the serum sodium ionic concentration and negatively correlated with the serum Alb(r = 0.486, P < 0.01; r = 0.490, P < 0.01, respectively). In conclusion, the sodium retention with nephrotic syndrome might be correlated with reduction of secreted sodium in the kidney, suggesting that ET-1 plays an important role in pathogenesis.

Aldosterone↗
PubMed1998

[Study on the preventive effect of tea on DNA damage of the buccal mucosa cells in oral leukoplakias induce by cigarette smoking].

In order to study the preventive effect of tea on DNA damage induced by cigarette smoking and to provide further evidence on the protective effects of tea in human cancer, a 6-month, double-blind and randomized placebo-controlled intervention trial was carried out. The effect of tea on micronuclei frequency in exfoliated oral buccal mucosa cells in 36 oral leukoplakias of smokers was investigated. A kind of mixed tea given in an oral dose of 3 g/day and a concentration of 0.1% smeared on mucosa lession three times a day for 3 months and 6 months, significantly decreased the micronuclei formation in exfoliated oral buccal mucosa cells in subjects with oral leukoplakias. In contrast, there was no change in the micronuclei frequency after 6 months in the placebo group. The results indicate that mixed tea may reduce the oral cancer risk by preventing DNA damage in oral leukopiakias induced by cigarette smoking.

Adult↗
PubMed1998

[VP-16 and VM-26 plus platinum drugs combined with radiotherapy in the treatment of small cell lung cancer].

OBJECTIVE: To compare the clinical efficacy of VP-16(etoposide) with VM-26(teniposide) both plus platinum drugs combined with radiotherapy in the treatment of patients with small cell lung cancer(SCLC). METHODS: Seventy-four cases of SCLC were studied retrospectively. Forty-three patients were treated with VP-16 + DDP + CTX or VP-16 + DDP, the other 31 patients were treated with VM-26 + DDP or VM-26 + Carboplatin. The treatment of both groups was combined with radiotherapy. RESULTS: There was no significant difference between VP-16 and VM-26 groups in response rate, 2-year-survival rate, and brain metastasis rate. But the blood toxicity was more serious in VM-26 group than in VP-16 group; 3-4 stage toxicity rate was 58.06% versus 27.91%. CONCLUSION: The results indicate that both VP-16 and VM-26 combined with platinum drugs were effective chemotherapy protocols. The authors suggest choosing VP-16 protocols as the first choice for previously untreated SCLC patients.

Adult↗
PubMed1998

[Analysis of X-ray images of giant-cell tumor of bone of rare locations].

OBJECTIVE: To analyse X-ray images of giant-cell tumor of rare locations. METHODS: To retrospectively review the X-ray films, CT scans and arteriograms of 48 cases of surgically and/or pathologically confirmed giant-cell tumor of bone of rare locations. RESULTS: Of the 48 cases, expansive cystic destructive changes of the bone with soap-bubble like appearence was found in 30 cases, osteolytic destruction in 10 cases, soft tissue mass outside of bone with sinking, flattening and local expanding of bone in 4 cases, invading into neighboring bone in 4 cases, hyperplasia and sclerosis of bone in 3 cases and staining of abnormal blood vessels and tumors in 3 cases. CONCLUSION: For the diagnosis of giant-cell tumor of bone of rare locations, X-ray plain film is of great value. CT is even better than plain film; arteriogram is helpful for diagnosis and treatment planning.

Adolescent↗
PubMed1998

[Telomerase activity in infiltration ductal carcinoma of breast].

OBJECTIVES: To compare telomerase activity of infiltration ductal carcinoma of breast with that of benign breast changes and to analyze the significance of telomerase activity in diagnosis of malignancy. METHOD: Telomerase activity was detected in 61 cases of infiltration ductal carcinomas of breast and 14 cases of benign changed breast using TRAP assay. RESULTS: Telomerase activity was detected in 49 of 61 (80.3%) cases of infiltration ductal carcinoma. Telomerase activity in infiltration ductal carcinoma was not related tumor grades, tumor size, lymph node metastasis status, even tumor tissue estogen receptor(ER) and progesterone receptor(PR) status. Telomerase activity was not present in 5 cases of breast fibrocystic disease. Weak telomerase activity was detected in 4 of 9 cases of breast fibroadenoma. These suggested that telomerase activity acquires in very early stage of breast cancer. CONCLUSION: Telomerase activity is only detected in most of infiltration ductal carcinomas of breast and few cases of fibroadenoma. Telomerase activity may play an important role in the development of breast cancer.

Breast Neoplasms↗
PubMed1998

[Costimulatory B7 molecules in drug induced interstitial nephritis and IgA nephropathy with tubulointerstitial injury].

OBJECTIVE: To evaluate the role of costimulatory B7 molecules in the pathogenesis of drug induced interstitial nephritis(D-TIN) and IgA nephropathy with severe tubulointerstitial injury(IgAN). METHODS: Renal biopsy materials from D-TIN(n = 15) and IgAN(n = 15) were used. Cadaveric donors for kidney transplantation(n = 10) served as normal controls. The lymphocyte subsets and the expression of B7-1, B7-2 and HLA-DR in the renal tissue were analyzed by immunohistochemistry staining. RESULTS: CD4+ and CD8+ cells in the interstitium markedly increased in patients with D-TIN. Parallelly, B7-1 and B7-2 expressing cells in the interstitium also augmented in this group of patients. The expression of B7-1 and HLA-DR on the renal tubular cells increased in patients with D-TIN. Although CD4+ and CD8+ cells increased in the interstitium of IgAN, the B7-1 and B7-2 expressing cells in the interstitium were not different from those of the normal controls. Although the renal tubular expression of B7-1 was upregulated in IgAN, the expression of HLA-DR kept in the normal range. CONCLUSION: These results indicate that the costimulatory molecules mediated T cell activation plays an important role in the pathogenesis of D-TIN. The interstitial infiltrating and tubular cells both act as an antigen presenting cells in the initiation of immune injury in D-TIN. However, such evidence has not been found in patients with IgAN.

Adult↗
PubMed1998

[Insulin receptor substrate-1 and glucose transporter gene polymorphisms in noninsulin-dependent diabetes mellitus].

OBJECTIVE: To evaluate the role of insulin receptor substrate-1 (IRS-1) and glucose transporter-1 (GLUT1) gene polymorphisms in Chinese patients with noninsulin-dependent diabetes mellitus (NIDDM) and diabetic neophropathy (DN). METHODS: Aminoacid polymorphism in codon 972 of IRS-1 gene and the polymorphic Xba I site of GLUT1 gene were analyzed by PCR-RFLP in 131 patients with NIDDM and 124 normal subjects. DN was defined as persistent albuminuria and/or impaired renal function, without known cause of renal diseases other than diabetes. Insulin sensitivity index (ISI) and body mass index (BMI) were also calculated. RESULTS: The distribution of IRS-1 gene polymorphism showed no difference between patients with NIDDM and normal controls. The frequencies of Xba I (+/-) genotype (59% vs. 33%, P < 0.01) and Xba I (-) allele (37% vs. 21%, P < 0.01) were significantly higher in NIDDM patients than in normal subjects. To further explore the linkage of GLUT1 gene polymorphism with DN, we examined the GLUT1 genotype of NIDDM patients with or without renal damage. The frequency of Xba I (+/-) genotype (75% vs. 44%, P < 0.01) and Xba I (-) allele (44% vs. 29%, P < 0.05) was significantly higher in NIDDM patients with diabetic nephropathy than either those without nephropathy or normal subjects. However, there were no significant differences of GLUT1 genotype and allele frequency in NIDDM patients without nephropathy and normal controls. The presence of Xba I (-) allele appeared to have a strong association with the development of diabetic nephropathy. The odds ratio was 1.915, and the 95% confidence interval was 1.044-3.514. The association of Xba I (-) allele of GLUT1 gene with NIDDM partly reflected their close association with DN. Although there was no correlation between the gene polymorphism of GLUT1 and BMI, patients carrying the Xba I (-) allele showed a lower ISI. CONCLUSION: No association was found between the gene polymorphism of IRS-1 and NIDDM. THe Xba I (-) allele of GLUT1 gene might be taken as a genetic marker of NIDDM with diabetic nephropathy and this genetic susceptibility appears to be associated with the insulin resistance in patients with NIDDM.

Adult↗
PubMed1998

[Comparison of different surgical procedures for urinary stress incontinence].

OBJECTIVE: Comparison of different surgical procedures for urinary stress incontinence (USI). METHODS: 95 patients with and/or accompanying USI were treated operatively in a prospectively randomized manner. RESULTS: The cure rate of colposuspension group 3 months after operation was 93% and was higher than 69% after Kelly operation (P < 0.05). But the cure rate 12 months after operation decreased to 74% and 58% respectively (P > 0.05). The percentage of abnormal sexual life was lower in the colposuspension group (4%) than that of those having Kelly operation (7%). The average days and times of intubation in the colposuspension group were more than in Kelly operation group (P < 0.05). CONCLUSION: The cure rate of colposuspension 3 months was better than that of the Kelly operation. The cure rate at 1 year was similar in the two procedures. Transient urinary retention occurred more after in the colposuspension group.

Female↗