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D Y Liu

Publications and source records attributed to D Y Liu.

At least 73 records · Page 4Linked to original sources
PubMed1994

The use of anticlusterin monoclonal antibodies for the combined assessment of human sperm morphology and acrosome integrity.

Clusterin is an abundant protein in the human male reproductive tract which appears to be produced by the testis, epididymis and the seminal vesicles. Using monoclonal antibodies and an amplified immunoperoxidase technique, we have identified two apparently biochemically distinct forms of clusterin on human spermatozoa. Morphologically abnormal spermatozoa have an extensive surface coating of conventional 80 kDa native clusterin, but this form of clusterin is not detectable on normal spermatozoa. Normal spermatozoa, however, contain within the acrosomal cap a different form of clusterin, reactive with an anticlusterin alpha-chain antibody. Agglutinated spermatozoa, most of which are grossly abnormal, were intensely labelled with the antibody against conventional 80 kDa clusterin, suggesting that the 'clustering' properties of this protein may play a role in the aggregation of abnormal spermatozoa. Anticlusterin monoclonal antibodies may be useful for semen analysis. Staining spermatozoa with anticlusterin monoclonal antibodies is a technically simple method which provides a visually obvious means of assessing spermatozoa morphology and acrosome status simultaneously. The current data also suggest that different functions of clusterin in the reproductive tract may be attributed to different molecular forms of the protein.

Acrosome↗
PubMed1994

Disordered acrosome reaction of spermatozoa bound to the zona pellucida: a newly discovered sperm defect causing infertility with reduced sperm-zona pellucida penetration and reduced fertilization in vitro.

It is believed that during the process of human fertilization, acrosome-intact spermatozoa bind to the surface of the zona pellucida which triggers the acrosome reaction and the enzymes released facilitate sperm penetration through the zona pellucida. We describe here reduced frequency of the acrosome reaction on the zona pellucida as a cause of infertility in 10 couples with long durations of infertility (average 6 years) and low (< 15%, n = 3) or zero (n = 7) fertilization rates in vitro. Sperm concentration, motility, velocity (Hamilton-Thorn), morphology and DNA normality were within the normal range in all the patients. Electron microscopy of spermatozoa did not reveal any specific ultrastructural defects. All couples were negative for antisperm antibodies by immunobead tests. Oocytes from other patients which failed to fertilize in in-vitro fertilization and normal donor spermatozoa were used as controls for sperm-zona pellucida binding and penetration experiments. Acrosome status of spermatozoa bound to the zona pellucida was assessed with a fluorescent lectin and electron microscopy. The mean number of spermatozoa bound to the zona pellucida was not significantly different between patients and controls. However, the acrosome reaction of spermatozoa bound to the zona pellucida after 2 h incubation was significantly lower (P < 0.001) in the patients (mean 5%, range 0-16) than in the controls (mean 68%, range 44-96). No zona pellucida (out of 40) was penetrated by patient spermatozoa whereas most (39/40) zonae were penetrated by control spermatozoa (average 27 spermatozoa/four zonae pellucidae).(ABSTRACT TRUNCATED AT 250 WORDS)

Acrosin↗
PubMed1994

[The changes in retinol-binding protein, N-acetyl-beta-glucosaminidase, albumin and IgG in urine before and after ESWL].

The retinol-binding protein (RBP), N-acetyl-beta-glucosaminidase, (NAG) albumin (alb) and IgG in urine were measured from 67 patients with urinary stone before and after ESWL. The results showed that the amount of alb, IgG and RBP in urine was obviously increased for the patients with renal, upper ureteral or lower ureteral stone associated with hydronephrosis. ESWL may injure the glomerule and tubules by direct or indirect action. 2 weeks after ESWL, the alb, IgG and RBP in urine returned to normal in 56.8%, 70.3% and 51.4% of cases respectively. Therefore we suggest that retreatment should be put off as late as 2 weeks after the first ESWL. However, it is not limited for retreatment of lower ureteral stones without hydro nephrosis.

Acetylglucosaminidase↗
PubMed1994

[Diagnostic value of imaging in localizing primary aldosteronism].

From May 1985 to March 1993, 159 patients with primary aldosteronism were treated surgically. The results of localization of aldosteronomas by B-type ultrasonography, CT and scintigraphy in 103 were compared with pathological results. The accurate rate of the modalities was 80.6%, 75.8% and 67.4% respectively. As a routine, we usually employ sonography and CT for localizing aldosteronomas. Only when difficulty was encountered with these two methods, scintigraphy was added. In our series, an accurate rate of 96.1% was obtained in surgical explorations with these imaging examinations with a consideration of clinical data.

Adenoma↗
PubMed1994

Activation of bovine factor IX by the reaction product of bovine factor VII and human tissue factor.

A study was carried out on the alternate activation of factor IX (FIX) by bovine FVII and human tissue factor (TF) rather than by activated factor XI (FXIa). The reaction product of bovine FVII and human TF functioned as a FIX activator in the assay system used. Published studies suggest that in the presence of Ca2+ ions, the complex of human FVII-TF readily activates both human FIX and human FX, and at low TF concentrations, FIX appears to be the preferred substrate for the reaction product of FVII and TF. This may explain the discrepancy between the mild bleeding of hereditary FXI deficiency and the severe bleeding of hereditary FIX deficiency. The results obtained with bovine FVII and a crude human TF preparation confirm that at low TF concentrations, bovine FIX is the preferred substrate rather than FX. At higher TF concentrations, bovine FX was rapidly activated.

Animals↗
PubMed1993

Inhibition of acrosin activity with a trypsin inhibitor blocks human sperm penetration of the zona pellucida.

To evaluate the role of acrosin in human sperm penetration of the zona pellucida (ZP), sperm-oocyte interaction was studied after acrosin activity was blocked with soybean trypsin inhibitor (SBTI). Oocytes that had failed to fertilize because of sperm pathology in a clinical in vitro fertilization program were used to assess sperm binding to and penetration into the ZP. The acrosome reaction of sperm bound to the ZP was determined using fluorescein-labeled Pisum sativum agglutinin after sperm were removed from the ZP. Acrosin activity, determined by a gelatin substrate film method, was severely inhibited by 2 mg/ml SBTI. Sperm motility and movement characteristics, assessed by a Hamilton-Thorn motility analyzer, were unchanged after 6-h incubation with SBTI. Inhibition of acrosin activity did not affect the number of sperm bound to the ZP but completely blocked sperm penetration of the ZP after a 5-h incubation. SBTI did not influence the spontaneous acrosome loss of sperm in culture medium after 6-h and 20-h incubations, but the percentage of acrosome-reacted sperm bound to the ZP was significantly reduced. It was concluded that acrosin activity plays a key role in sperm-zona interaction in humans. Motile sperm are unable to penetrate the ZP when acrosin activity is inhibited. This might result from interference with a phase of the sperm-ZP binding reaction or with a lytic action of acrosin. Also, acrosin may be involved in the acrosome reaction induced by sperm binding to the ZP.

Acrosin↗
PubMed1993

[Diagnosis and treatment of recurrent pheochromocytoma].

From 1959 to 1992, 216 patients with pheochromocytoma were treated by complete resection of the tumor in our hospital. Ten patients (4.6%) were found to have recurrent pheochromocytoma 1-21 years after operation. Five patients underwent surgical removal of the tumor and normally lived for 1 to 4 years. In remaining 5 patients malignant change was confirmed. Two patients died of extensive metastasis. One who had a recurrent tumor metastasis in the thoracic vertebra was treated with dibenzyline for 9 years. The remaining 2 patients were treated by 131I-MIBG. To prevent or minimize the incidence of recurrence of pheochromocytoma, we suggest: (1) avoid needle biopsy of the tumor, (2) prevent a rupture of the tumor capsule, (3) ligate the veins around the tumor as early as possible and (4) resect the tumor completely or perform a subtotal or total removal of the involved adrenal gland in unilateral cases.

Adolescent↗
PubMed1993

[Application of double-J stent in treatment of pelvic-ureteric].

From May 1988 to October 1991, we used double-J tube for uretero-vesical drainage as postoperative stent in 12 cases of pelvic-ureteric junction stricture. The tube was inserted either by a percutaneous antegrade procedure or through the operative site. Postoperative follow-up observation revealed satisfactory results in all cases. Compared with the traditional method, it is advantageous in providing early convalescence, preventing infection, promoting healing of the operative site or the anastomosis site, and shortening the period of hospitalization.

Adolescent↗
PubMed1992

Integrins as a primary signal transduction molecule regulating monocyte immediate-early gene induction.

Integrins are cell surface receptors found on monocytes that facilitate adhesion to both cellular and extracellular substrates. These integrins are thought to be involved in the selective gene induction observed after monocyte adhesion to various extracellular matrices. To investigate this hypothesis, we stimulated monocytes with monoclonal antibodies to different integrin receptors to specifically mimic the integrin receptor-ligand interactions. Engagement of the common beta chain of the beta 1 subfamily of integrins resulted in expression of the inflammatory mediator genes, interleukin 1 beta, interleukin 1 receptor antagonist, and monocyte adherence-derived inflammatory gene 6 (MAD-6), whereas engagement of the common beta chain of the beta 2 family did not. Furthermore, to characterize integrin-mediated gene induction, we examined the ability of antibodies to the alpha chain of integrin receptors to regulate gene expression. Engagement of the very late antigen 4 (VLA-4) receptor resulted in induction of all the mediator genes. Receptor crosslinking was required because individual Fab fragments were unable to stimulate gene induction whereas the divalent F(ab')2 fragment and the whole IgG molecule could. Interleukin 1 beta secretion was dependent on the anti-integrin antibody used. Some antibodies required a second signal and, for others, direct engagement was sufficient for protein production. In conclusion, engagement of integrin receptors regulated the production of both inflammatory mediator mRNA and protein. These results suggest that integrin-dependent recognition and adherence may provide the key signals for initiation of the inflammatory response during monocyte diapedesis.

Antibodies, Monoclonal↗
PubMed1992

cDNA for Mo3, a monocyte activation antigen, encodes the human receptor for urokinase plasminogen activator.

We have cloned the cDNA for Mo3, an activation Ag expressed by human monocytes and myelomonocytic cell lines after stimulation by PMA, LPS, muramyl dipeptide, certain cytokines, and cAMP agonists. We have previously shown that Mo3 expression in vivo is associated predominantly with macrophages in inflammatory sites. Mo3 is a highly glycosylated protein of about 50 kDa in monocytes and U-937 cells and is anchored to the plasma membrane by glycosyl-phosphatidylinositol linkage. We purified Mo3 protein by cleavage from the U-937 cell surface with phosphatidylinositol-specific phospholipase C, followed by affinity chromatography using a mAb. An internal peptide sequence was determined and used to design oligonucleotide probes for screening an expression cDNA library. Nucleotide sequencing indicated that the complete coding sequence encodes 335 amino acids, including a predicted signal peptide of 22 residues and a hydrophobic C-terminal portion that is probably cleaved during formation of the GPI linkage. The resulting mature protein of about 290 amino acids is consistent with the 29-kDa molecular mass of deglycosylated Mo3. A Northern blot of RNA from U-937 cells revealed a 1.5-kb band that was induced by PMA treatment. Mo3 cDNA was transfected into Cos cells and surface expression of Mo3 was detected by ELISA using various anti-Mo3 mAb. We performed a computer search of the National Biomedical Research Foundation database and found that Mo3 is identical to the human receptor for the urokinase plasminogen activator (uPA-R). Purified soluble Mo3, as well as anti-Mo3 antibodies, were able to block uPA binding to its receptor on U-937 cells, indicating that Mo3 is indeed uPA-R. The use of these anti-Mo3 antibodies may be helpful in assessing the role of uPA-R in processes such as inflammation and tumor invasion.

Amino Acid Sequence↗
PubMed1992

Evaluation of hypothesis testing for comparing two populations using NONMEM analysis.

In a simulation study of inference on population pharmacokinetic parameters, two methods of performing tests of hypotheses comparing two populations using NONMEM were evaluated. These two methods are the test based upon 95% confidence intervals and the likelihood ratio test. Data were simulated according to a monoexponential model and, in that context, power curves for each test were generated for (i) the ratio of mean clearance and (ii) the ratio of the population standard deviations of clearance. To generate the power curves, a range of these parameters was employed; other pharmacokinetic parameters were selected to reflect the variability typically present in a Phase II clinical trial. For tests comparing the means, the confidence interval tests had approximately the same power as the likelihood ratio tests and were consistently more faithful to the nominal level of significance. For comparison of the standard deviations, and when the volume of information available was relatively small, however, the likelihood ratio test was more able to detect differences between the two groups. These results were then compared to results on parameter estimation in order to gain insight into the question of power. As an example, the nonnormality of estimates of the ratio of standard deviations plays an important role in explaining the low power for the confidence interval tests. We conclude that, except for the situation of modeling standard deviations with only sparse information, NONMEM produces tests of significance that are effective at detecting clinically significant differences between two populations.

Computer Simulation↗
PubMed1992

Tests of human sperm function and fertilization in vitro.

OBJECTIVE: To review recent studies on the development of new tests of human sperm function and evaluation of which sperm characteristics are most important for fertilization in vitro by logistic regression analysis. STUDY SELECTION: Recent studies on the relationship between putative and new tests of human sperm function and fertility in vitro or in vivo are discussed in this review. Some physiological and technical aspects are included. MAIN OUTCOME MEASURES: Fertilization rates in vitro and sperm tests including standard semen analysis, improved morphology assessment, objective assessment of sperm motility and movement characteristics, nuclear maturity, hypo-osmotic swelling, the acrosome and the acrosome reaction, acrosin activity, human sperm-hamster oocyte penetration assay, and sperm-zona pellucida (ZP) and sperm-oolemma binding. RESULTS: The percentages of sperm with normal morphology and a normal intact acrosome, mean linearity, and the number of sperm binding to the ZP were highly significant related to fertilization rates in vitro. Other sperm tests evaluated usually provided no additional information about fertilization rates. The human ZP is highly selective for binding of morphologically normal sperm. Acrosome-reacted human sperm have little or no ability to bind to the ZP. CONCLUSION: Results of in vitro fertilization can be used to evaluate tests of human sperm function. Logistic regression analysis is a powerful method for determining which groups of sperm characteristics are independently related to fertilization rates. Normal morphology, linearity, acrosome status, and sperm-ZP binding are the most important characteristics for fertilization in vitro.

Acrosome↗
PubMed1992

Sperm nuclear chromatin normality: relationship with sperm morphology, sperm-zona pellucida binding, and fertilization rates in vitro.

OBJECTIVE: To study whether the results of tests of sperm chromatin and deoxyribonucleic acid (DNA) normality are related to fertilization rates in vitro. DESIGN: Normal morphology, nuclear maturity determined by acidic aniline blue stain, and DNA normality determined by acridine orange fluorescence of sperm in insemination medium and the number of sperm bound to the zona pellucida (ZP) of the oocytes that had failed to fertilize in vitro were determined. The relationship between sperm test results and fertilization rates were analyzed by logistic regression. SETTING: Samples were obtained from patients undergoing in vitro fertilization (IVF) treatment. RESULTS: The number of sperm bound to the ZP, the percentage of sperm with normal morphology, and the percentage of sperm with normal DNA were the most significant factors related to fertilization rates in vitro. In patients with normal morphology > or = 15% or with > 10 sperm bound per ZP, the percentage of sperm with normal DNA, the number of sperm bound to the ZP, and motility grade were significantly related to IVF rates. CONCLUSION: In patients with normal morphology > or = 15%, failure of fertilization may be because of defects of sperm-ZP binding or abnormal DNA. Assessment of DNA normality of motile sperm in the insemination medium may aid prediction of fertilization rates in addition to normal morphology and sperm-ZP binding.

Acridine Orange↗
PubMed1992

Comparison of Percoll, mini-Percoll and swim-up methods for sperm preparation from abnormal semen samples.

Two methods of density gradient centrifugation, Percoll (P) and mini-Percoll (MP), were compared with the swim-up technique for preparing spermatozoa from each of 40 abnormal semen samples. P and MP produced similar results with a mean recovery of spermatozoa with progressive motility which was significantly higher (18-19%) than that achieved with swim-up (5%). However, the swim-up method resulted in the recovery of spermatozoa with a higher mean motility (89 versus 58%), velocity (69 versus 56 microns/s), percentage with normal morphology (22 versus 16%) and intact acrosomes (61 versus 36%) than P and MP. The mean amplitude of lateral head displacement was the only characteristic of spermatozoa in semen which correlated with the recoveries of motile spermatozoa. Combining MP and swim-up methods for 10 samples produced a higher recovery (11 versus 6.9%) of spermatozoa with significantly better mean motility (94 versus 87%) than did swim-up alone. Although P and MP resulted in greater yields of motile spermatozoa than the swim-up preparation, the latter procedure selected higher proportions of spermatozoa with improved characteristics (velocity, intact acrosomes and normal morphology) which correlate with fertilization rates in vitro. It is concluded that P and MP are not superior to swim-up. However, sequential MP and swim-up preparation improves yields of high quality spermatozoa from some abnormal semen samples and therefore has potential for improving fertilization rates.

Cell Separation↗
PubMed1992

Morphology of spermatozoa bound to the zona pellucida of human oocytes that failed to fertilize in vitro.

The morphology of spermatozoa bound to the zona pellucida (ZP) of 264 oocytes that had failed to fertilize in 58 in vitro fertilization procedures was studied by light microscopy. The percentage of spermatozoa with normal morphology bound to the ZP (mean 77, range 8-100) was significantly higher than in the insemination medium (mean 42, range 2-80). The abnormal spermatozoa bound to the ZP had small oval (47%), pyriform (46%), amorphous (5%) and tapering (2%) heads. Other abnormalities of morphology were not observed in ZP-bound spermatozoa. The mean rates of binding to the ZP of spermatozoa with normal morphology (44, 95% confidence limits 42-46, number bound/ZP/10(5)/ml inseminated) were much higher than for abnormal spermatozoa with small oval 6.5 (5.5-7.6), pyriform 5.9 (4.8-7.3), amorphous 1.0 (0.5-2.0) and tapering 2.5 (1.2-5.3) heads. The morphologically abnormal forms not found on the ZP were infrequent in the insemination medium (tail defects, large oval, round, pin and duplicate heads and cytoplasmic droplets) but upper 95% confidence limits for standardized binding ratios of less than 60% indicated that these were unlikely to bind to the zona with rates approaching those of normal spermatozoa (standardized binding ratio 180%). A large number of uniformly normal spermatozoa bound to the ZP when the percentage normal morphology in the insemination medium was greater than 40%. The proportions of abnormal spermatozoa in the insemination medium. Spermatozoon head dimensions were measured with a micrometer in samples from 14 patients. While there were no consistent changes in all samples, the means for head width and area were significantly larger and the ratio of the length to width was smaller for spermatozoa on the ZP than for those in the insemination medium. The head length and ratio of length to width of spermatozoa in samples with good morphology were significantly less than in samples with poor morphology. The percentage of spermatozoa with normal morphology, motility and the ratio of head length to width in the insemination medium were positively correlated with the percentage of spermatozoa with normal morphology bound to the ZP. Logistic regression analysis showed that the diagnosis of tubal infertility and the rate of binding of spermatozoa with normal morphology to the ZP were positively related to fertilization rates in vitro while the rate of binding of spermatozoa with pyriform heads was negatively related. In conclusion. human ZP are highly selective for spermatozoa with normal morphology. The frequency of binding of abnormal spermatozoa to the ZP was mainly dependent on semen quality.(ABSTRACT TRUNCATED AT 400 WORDS)

Female↗
PubMed1992

Effects of tumor necrosis factor alpha (TNF-alpha) on collagen arthritis.

Louvain rats were administered tumor necrosis factor alpha (TNF-alpha) via a continuous osmotic infusion pump. These rats were then immunized with native type II collagen (CII) to determine the effects of exogenous TNF-alpha on collagen-induced arthritis (CIA), an animal model of rheumatoid arthritis (RA). In this highly susceptible strain, 100% of experimental and control rats developed arthritis although TNF-alpha-treated rats had more severe disease as judged by both clinical and blinded radiographic parameters. Humoral responses to collagen were high in both groups, but cellular responses to CII were augmented by TNF-alpha. Serum IL-6 levels were significantly increased in all arthritic rats. This study suggests that TNF-alpha is a proinflammatory cytokine in CIA and that future studies targeting TNF-alpha might be therapeutic.

Animals↗
PubMed1992

[Percutaneous nephrostomy as a pretreatment in extracorporeal shockwave lithotripsy].

ESWL was performed in 572 patients with renal and ureteral stones between Dec. 1988 and Dec. 1990. All the patients recovered uneventfully without any serious complications. In 6 of these patients with bilateral urinary stones complicated by bilateral hydronephrosis or azotemia, unilateral percutaneous nephrostomy was done before ESWL. We conclude that in such cases a unilateral percutaneous nephrostomy before ESWL is helpful in reducing renal pelvic pressure, improving renal function, decreasing complication and shortening the period of treatment.

Adult↗