Biomedical subjects

Y C Lin

Publications and source records attributed to Y C Lin.

At least 109 records · Page 6Linked to original sources

PubMed2000

Clinical implications of intracytoplasmic sperm injection using cryopreserved testicular spermatozoa from men with azoospermia.

OBJECTIVE: To investigate whether sperm obtained by testicular sperm extraction (TESE) and cryopreserved well before intracytoplasmic sperm injection (ICSI) can serve as an effective sperm source. STUDY DESIGN: The role of cryopreserved testicular spermatozoa was evaluated in a retrospective analysis of consecutive ICSI cycles using fresh or cryopreserved sperm; they were followed by prospective, planned treatment using cryopreserved sperm with a modified ICSI procedure. Sixteen men (22 cycles) with obstructive or nonobstructive azoospermia were included in the retrospective analysis. Another 25 men (29 cycles) were in the planned treatment group. Following these series, the pregnancy outcomes were compared between ICSI cycles with fresh or cryopreserved testicular sperm. RESULTS: In the retrospective phase, 14 ICSI cycles were performed using fresh sperm, with 8 using cryopreserved sperm. There were no statistically significant differences between the two groups in any outcome measure. Planned treatment with cryopreserved sperm resulted in a fertilization rate of 84% and an embryo transfer rate of 89%. Thirteen couples (44%) achieved pregnancy (five ongoing, six delivered). These rates were similar to those in the retrospective phase of the study. All couples in the planned cryopreservation group had multiple aliquots (6.5 +/- 2.1) of sperm remaining after the first cycle. CONCLUSION: Cryopreserved sperm obtained by TESE can be used as an effective sperm source in ICSI cycles. Planned cryopreservation allows multiple aliquots to be stored for use in subsequent cycles and thus avoids the need for repeat biopsies.

Adult↗

PubMed2000

The effects of Tai Chi Chuan on postural stability in the elderly: preliminary report.

BACKGROUND: Tai chi chuan (TCC) is a traditional Chinese conditioning exercise, consisting of a series of graceful movements linked together in a continuous sequence so that the body is constantly shifting from one foot to the other. We propose that subjects practicing TCC will have better postural control and stability than will active non-practitioners. METHODS: We compare static and dynamic postural controls in 14 TCC practitioners and 14 healthy active older adults using the Smart Balance Master System. The TCC group, containing 7 male and 7 female subjects (mean age, 70.9 +/- 3.3 years), had been practicing TCC regularly for 2 to 35 years. The control group included 4 male and 10 female healthy and active older subjects (mean age, 69.1 +/- 3.1 years), with age and body size matched to the TCC group. RESULTS: The results of static postural control tests showed no differences between the TCC and control groups under simple conditions (eyes open, eyes closed, swaying vision, and eyes open with swaying surface), but in the more complicated conditions (eyes closed with sway-referenced support and sway-referenced vision and support), the TCC group had significantly better results than the control group. In the dynamic balance test, the TCC group had significantly better results only in the rhythmic forward-backward weight-shifting test. CONCLUSION: Our data demonstrate that regular TCC practitioners have better postural stability, especially in the more complicated conditions with disturbed visual and somatosensory conditions.

Aged↗

PubMed2000

Seminal plasma zinc levels and sperm motion characteristics in infertile samples.

BACKGROUND: Zinc (Zn) in seminal plasma stabilizes the cell membrane and nuclear chromatin of spermatozoa. It may also have an antibacterial function. However, extremely high concentrations of Zn (10 to 100 x the normal range) may inhibit sperm motility and the function of the mannose receptor on the sperm head. In this study, we analyzed the correlation between Zn levels in seminal plasma and the characteristics of semen as measured by conventional and computer aided sperm analysis (CASA). METHODS: One hundred fifteen infertile couples were recruited for conventional semen analysis and CASA from December 1995 through January 1996, and Zn levels in semen samples were determined by flame atomic absorption spectroscopy (AAS). RESULTS: A good correlation in a positive direction (r = 0.73, p = 0.0001) was noted between the total amount of Zn per ejaculate and the Zn concentration. The Zn concentration in seminal plasma was negatively correlated with the seminal pH (r = -0.35, p = 0.0081). There was no significant correlation between the total amount of Zn per ejaculate and sperm characteristics, including sperm count, motility (% sperm count), progressive motility (% motility), rapid motility (% motility), average path velocity (VAP, microns/s), straight-line velocity (VSL, microns/s), curvilinear velocity (VCL, microns/s), amplitude of lateral head displacement (ALH, microns), beat/cross frequency (BCF, beats/s), straightness (STR), and linearity (LIN). There was also no significant correlation between the Zn concentration in seminal plasma and the above sperm characteristics. CONCLUSION: The characteristics of semen as determined by conventional semen analysis or CASA bore no correlation with total seminal Zn amount or Zn concentrations in the ejaculates. Routine determination of the Zn concentration in seminal plasma offers no advantages in infertility work-ups.

Humans↗

PubMed2000

Control of idiopathic ventricular fibrillation by implantable cardioverter-defibrillator in a child who survived sudden death.

Idiopathic ventricular fibrillation (VF) is extremely rare in children who have not previously undergone cardiac surgery. Patients resuscitated from idiopathic VF remain at risk for recurrence. The use of an implantable cardioverter-defibrillator (ICD) effectively prevents such recurrences. We report the case of a 12-year-old girl who had a history of recurrent syncope and had survived an episode of VF. Serial studies after prolonged but successful resuscitation, including echocardiography, an electrocardiogram (ECG), and coronary angiography failed to reveal abnormal cardiac structures responsible for VF. No abnormal conduction pathways or abnormal early or late after depolarization were found on electrophysiologic study. The ST segments of the 12-lead ECG remained normal after procainamide challenge. The patient underwent ICD implantation 2 weeks after admission and syncope did not recur during a follow-up of 14 months. This report emphasizes that idiopathic VF may be responsible for syncope in children. ICD therapy prevents the recurrence of idiopathic VF and the associated risk of sudden death.

Child↗

PubMed2000

Malignant phyllodes tumor of the breast metastasizing to the pancreas: case report.

Phyllodes tumor of the breast, or cystosarcoma phyllodes, is an unusual breast tumor. It is usually considered a benign lesion but may have malignant potential. Only a small proportion of malignant phyllodes tumors will metastasize. A phyllodes tumor of the breast metastasizing to the pancreas is rare. This 39-year-old female patient initially presented to us with a 5 x 4 x 2 cm tumor of a right breast. After excision of the tumor, she received another wise excision for a local recurrence of the tumor. Three years had passed when she started having hematemesis and tarry stools intermittently over a period of about one month. Clinical evaluation disclosed a huge mass with an ulcerated and bloody base over the second portion of the duodenum. A pancreatoduodenectomy was then performed. During the postoperative recovery period, a rapidly enlarging tumor of the right breast was noted. She subsequently underwent a total mastectomy of the right breast. Both the duodenal tumor and the breast tumor were found to be malignant phyllodes tumors. The rarity of this kind of patient and presentation is discussed.

Adult↗

PubMed2000

Antagonistic effects of 3 sesquiterpene lactones from Atractylodes macrocephala Koidz on rat uterine contraction in vitro.

AIM: To study the effects of three sesquiterpene lactones: atractylenolide I (8,9-dehydroasterolide, B), 4,15-epoxy-8 beta-hydroxyasterolide (C), and atractylenolide III (8 beta-hydroasterolide, D) from Atractylodes macrocephala Koidz, on rat isolated uterus smooth muscle. METHODS: Rat isolated uteri bathed in De Jalon I solution were used; acetylcholine (ACh), CaCl2, and oxytocin (Oxy) were used to evoke the contraction of uterus. RESULTS: B, C, and D 28 or 56 mumol.L-1 inhibited the spontaneous movement of uterus, reducing their rest force, contractile force, and movement ability. B 28 or 56 mumol.L-1 also slowed down the frequency of uterus spontaneous contraction, but C or D did not. B, C, or D 28 and 56 mumol.L-1 inhibited the uterine spasm induced by Oxy and ACh. Likewise, Ver 0.28 mumol.L-1, B, C, and D 28 or 56 mumol.L-1 relieved the contraction mediated by CaCl2 in high-KCl solution, but B, C, or D had not marked influence on the maximal response of uterus to CaCl2. CONCLUSION: B, C, and D inhibit the movement of uterus smooth muscle, and the mechanism is related to the inhibition of cholinergic system as well as Ca2+ movement.

Acetylcholine↗

PubMed2000

[Studies on technology of supercritical-CO2 fluid extraction for volatile oils and saikosaponins in Bupleurum chinense DC].

OBJECTIVE: To study the technology of supercritical-CO2 fluid extraction (SFE-CO2) for the volatile oils and saikosaponins in Bupleurum chinense. METHOD: Exploring the effects of pressure, temperature, extraction time, flow rate of CO2 and entrainers on the yield of the oils and saikosaponin-contained extracts; determining the optimum conditions for SFE-CO2; analyzing the oils by GC/MS and comparing the technology of SFE-CO2 with that of traditional steam distillation. RESULT: The optimum extraction conditions turned out to be--for volatile oils: pressure (EP) = 20 MPa, temperature (ET) = 30 degrees C, isolator I pressure (1P-I) = 12 MPa, temperature(1T-I) = 65 degrees C, isolator II pressure (1P-II) = 6 MPa, temperature (1T-II) = 40 degrees C, extraction time = 4 hours, and CO2 flow rate = 10-20 kg.(h.kg)-1 crude drug; for saikosaponins: EP = 30 MPa, ET = 65 degrees C, 1P I = 12 MPa, 1T I = 55 degrees C, 1P II = 6 MPa, 1T II = 43 degrees C, extraction time = 3 hours, entrainer = 60% ethanol, and CO2 flow rate = 20-25 kg.(h.kg)-1 crude drug. CONCLUSION: SFE-CO2 excels the traditional steam distillation in raising yield and reducing extraction time. The oils are composed of 22 constituents including caproaldehyde, and the saikosaponins can only be extracted with the help of entrainers under higher pressure and temperature.

Bupleurum↗

PubMed1999

Cytomegalovirus-encoded beta chemokine promotes monocyte-associated viremia in the host.

Chemokine homologs are encoded by many large DNA viruses, suggesting that they contribute to control of host leukocyte transmigration and trafficking during viral infection. Murine cytomegalovirus carries a CC (beta) chemokine homolog gene giving rise to two related proteins, murine cytomegalovirus chemokine 1 and 2 (MCK-1 and MCK-2). MCK-1 peptide was found to induce calcium signaling and adherence in murine peritoneal macrophages. Cells bearing human chemokine receptor CCR3 and the human macrophage THP1 cell line were responsive to MCK-1. This pattern suggested that MCK-1 might act as an agonist, promoting leukocyte trafficking during viral infection. Consistent with this prediction, MCK-1/MCK-2 mutant viruses exhibit dramatically reduced peak levels of monocyte-associated viremia in experimentally infected mice. Thus, MCK-1/MCK-2 appears to promote host leukocyte migration to initial sites of infection and may be responsible for attracting monocytes or macrophages that efficiently disseminate virus in the host.

Amino Acid Sequence↗

PubMed1999

Parathyroid hormone-related protein is a positive regulator of keratinocyte growth factor expression by normal dermal fibroblasts.

Parathyroid hormone-related protein (PTHrP), an important factor in the pathogenesis of humoral hypercalcemia of malignancy, is produced by many normal tissues, including the skin, where it regulates keratinocyte growth and differentiation and dermal fibroblast function. Keratinocyte growth factor (KGF), a member of the fibroblast growth factor (FGF) family, is a secretory product of stromal cells and functions as a mediator of epithelial cell growth and differentiation. Phenotypes of the skin in several transgenic mouse models, in which the KGF and PTHrP genes have been overexpressed or disrupted, suggest that these two factors interact in vivo to regulate homeostasis of the skin. In this study, we investigated the effects of KGF on PTHrP secretion and expression by normal human foreskin keratinocytes (NHFK) and the effects of PTHrP on KGF secretion and expression by normal human dermal fibroblasts (NHDF) in vitro. N-terminal PTHrP(1-36) increased KGF secretion, protein expression and mRNA expression by NHDF in a dose-dependent manner, however, KGF did not regulate PTHrP expression and secretion by NHFK. By flow cytometry, PTHrP also increased the percentage of NHDF producing KGF. Our results indicate that PTHrP produced by keratinocytes is a potential paracrine regulator of KGF expression by dermal fibroblasts in vivo. This paracrine regulation may explain, in part, the epidermal atrophy seen in the PTHrP null mice and epidermal hyperplasia seen in transgenic mice overexpressing PTHrP in their basal keratinocytes. Our results also suggest that PTHrP is an important mediator for the healing of skin wounds and growth of neoplasms of squamous origin.

Animals↗

PubMed1999

Differences in the regulation of fibroblast contraction of floating versus stressed collagen matrices.

To learn more about the regulation of contraction of collagen matrices by fibroblasts, we compared the ability of lysophosphatidic acid (LPA) and platelet-derived growth factor (PDGF) to stimulate contraction of floating and stressed collagen matrices. In floating collagen matrices, PDGF and LPA stimulated contraction with similar kinetics, but appeared to utilize complementary signaling pathways since contraction obtained by the combination of growth factors exceeded that observed with saturating concentrations of either alone. The PDGF-simulated pathway was selectively inhibited by the protein kinase inhibitor KT5926. In stressed collagen matrices, PDGF and LPA stimulated contraction with different kinetics, with LPA acting rapidly and PDGF acting only after an approximately 1-h lag period. Pertussis toxin, known to block signaling through the Gi class of heterotrimeric G-proteins, inhibited LPA-stimulated contraction of floating but not stressed matrices, suggesting that LPA-stimulated contraction depends on receptors coupled to different G-proteins in floating and stressed matrices. On the other hand, the Rho inhibitor C3 exotransferase blocked contraction of both floating and stressed collagen matrices. These results suggest the possibility that distinct signaling mechanisms regulate contraction of floating and stressed collagen matrices.

ADP Ribose Transferases↗

PubMed1999

Vocal cord paralysis and hypoventilation in a patient with suspected Leigh disease.

The authors report the case of a 16-month-old male with suspected Leigh disease, which was diagnosed on the basis of the clinical manifestations, abnormal lactate stimulation test, proton magnetic resonance spectroscopy, and neuroradiologic findings. Progressive stridor resulting from bilateral vocal cord paralysis and hypoventilation was evident. The authors suggest that for infants or children who exhibit vocal cord paralysis, mitochondrial disorders, such as Leigh disease, should be considered.

Humans↗

PubMed1999

Relationship of the human cumulus-free oocyte maturational profile with in vitro outcome parameters after intracytoplasmic sperm injection.

PURPOSE: We investigated whether the human oocyte maturational profile at the removal of cumulus/corona cells affects the fertilization rate and subsequent embryo quality after intracytoplasmic sperm injection. METHODS: A total of 1011 oocytes from 150 cycles was included in this retrospective analysis. Cumulus-free oocytes that were in prophase or metaphase I of meiosis at the removal of cumulus/corona cells were incubated in vitro until they reached metaphase II (in vitro-matured oocytes) and were then immediately injected with a single spermatozoa. Oocytes that were in metaphase II at the removal of cumulus/corona cells (MII oocytes) received sperm injection after 3-4 hr of preinjection incubation. RESULTS: The fertilization rate of the MII oocytes was significantly higher than that of in vitro-matured oocytes (81 vs 62%; P < 0.001). The cleavage rates were similar in the two groups (MII oocytes, 94%; in vitro-matured oocytes, 91%). However, MII oocytes had significantly higher percentages of good-quality embryos (grade 1-3 embryos, 87 vs 58%, P < 0.001) and embryos with high cumulative embryo scores (score 10-32 embryos, 62 vs 33%, P < 0.001). The mean cumulative embryo score of MII oocytes after fertilization was also higher than that of in vitro-matured oocytes (12.1 +/- 3.8 vs 8.8 +/- 3.4; P = 0.014). CONCLUSIONS: MII oocytes that extruded the first polar body at the removal of cumulus/corona cells had better fertilization rates and embryo morphology than in vitro-matured oocytes that extruded the first polar body following the removal of cumulus/corona cells and in vitro culture.

Embryo, Mammalian↗

PubMed1999

The fas and fas ligand pathways in liver allograft tolerance.

The Fas and Fas ligand (Fas/FasL) pathways may play a central role in cytotoxicity or immunoregulation in liver transplantation. Here, in an attempt to examine the role of Fas/FasL on drug-free tolerance, we measured mRNA levels of Fas/FasL in livers by reverse transcriptase-polymerase chain reaction (RT-PCR), and also protein levels of Fas/FasL in livers by immunohistochemistry and in serum by dot blot assay. PVG recipients bearing DA livers showed serious rejection between post-operative (POD) days 7 and 14, but this rejection was naturally overcome without any immunosuppression. Fas gene and protein products were expressed on almost every cell in livers taken from naive rats, and at any time point in both syngeneic and allogeneic orthotopic liver transplantation (OLT) rats. In contrast, FasL mRNA in DA livers was detectable at POD 2, peaked at POD 14, and declined at POD 63 in allogeneic OLT (DA-PVG). Although the FasL gene was detectable in isografts at POD 14, its expression was much lower than in allografts. The time course and localization of FasL expression indicated that the expression of FasL gradually switched from infiltrating cells to hepatocytes when the rejection was naturally overcome and tolerance was induced in this OLT model. Soluble Fas could constitutively be detected at any time point in the serum of the tolerogenic OLT (DA-PVG) rats and was not diminished during the rejection phase. Soluble FasL peaked at POD 14 in allogeneic OLT, while sFasL was significantly lower in the serum of normal and syngeneic OLT rats. These findings suggest that the Fas and FasL pathways, including soluble forms, may contribute to the control of the immune response in this drug-free tolerance OLT model.

Animals↗

PubMed1999

Outcomes after single injection caudal epidural versus continuous infusion epidural via caudal approach for postoperative analgesia in infants and children undergoing patent ductus arteriosus ligation.

Adequate postoperative analgesia enhances deep breathing and minimizes respiratory complications after thoracotomy. This study compares postoperative outcomes after single injection caudal epidural vs continuous infusion epidural via caudal approach for postoperative analgesia in infants and children undergoing thoracotomy for patent ductus arteriosus (PDA) ligation. A retrospective chart review was performed for 27 children who had undergone PDA ligation. The children were divided into three groups. We compared patient demographics, surgical duration, anaesthesia duration, length of ICU stay, incidence of emesis requiring treatment, time required to establish regular oral intake, requirement for supplemental intravenous opioids during the first postoperative day, and length of hospital stay. For paediatric patients undergoing PDA ligation, postoperative analgesia with continuous infusion epidural via caudal approach produced shorter ICU stay, less occurrence of postoperative emesis, earlier oral intake, elimination of intravenous opioid supplementation, and shorter hospital stay compared with single injection caudal epidural techniques.

Analgesia, Epidural↗

PubMed1999

Effects of cord blood transfer on the hematopoietic recovery following sublethal irradiation in MRL lpr/lpr mice.

The potential of cord blood (CB) to serve as a rich source of stem cells and stem cell factors is receiving increasing attention. In addition, perhaps because of the early ontogeny of these cells or the lack of surface antigens, cord blood stem cells do not appear to require close identity with the recipient. In the present pilot study, we investigated the presence of a hematopoiesis enhancing effect (HEE) by assaying the ability of human cord blood cells to augment hematopoiesis across a species barrier. For these experiments, autoimmune-prone MRL-Ipr/Ipr mice were exposed to sublethal levels of irradiation and cord blood administration to study the role of factors present in human cord blood in augmenting the rate of lymphopoiesis. This strain was chosen because of the increased presence of peripheral T and B subpopulations, namely the B-1 and CD4/CD8 double negative T-cell subpopulations, which do not arise directly from bone marrow precursors, but rather accumulate with age. MRL-Ipr/Ipr mice were sublethally irradiated and reconstituted with syngeneic bone marrow (BM) cells or with human cord blood cells or peripheral blood mononuclear cells (PBMC), or were left unreconstituted. At 2 weeks post-treatment, lymphoid populations in the spleen and lymph nodes were studied as a measure of hematopoiesis. Factors present in cord blood were able to augment hematopoiesis over that which occurred endogenously. At 2 weeks postirradiation, recipients of BM cells displayed the fastest rate of peripheral lymphoid recovery, nonreconstituted mice showed the slowest lymphoid recovery, and recipients of cord blood recovered their lymphoid populations at an intermediate rate. Similarly, myelopoiesis was increased in irradiated SJL/J recipients of human cord blood. Thus, human cord blood cells appear to produce/induce factors that may act as an adjunct to increase stem-cell activity.

Animals↗

PubMed1999

Risk of transient hyperammonemic encephalopathy in cancer patients who received continuous infusion of 5-fluorouracil with the complication of dehydration and infection.

From 1986 to 1998, 29 cancer patients who had 32 episodes of transient hyperammonemic encephalopathy related to continuous infusion of 5-fluorouracil (5-FU) were identified. None of the patients had decompensated liver disease. Onset of hyperammonemic encephalopathy varied from 0.5 to 5 days (mean: 2.6 +/- 1.3 days) after the initiation of chemotherapy. Plasma ammonium level ranged from 248 to 2387 microg% (mean: 626 +/- 431 microg%). Among the 32 episodes, 26 (81%) had various degrees of azotemia, 18 (56%) occurred during bacterial infections and 14 (44%) without infection occurred during periods of dehydration. Higher plasma ammonium levels and more rapid onset of hyperammonemia were seen in 18 patients with bacterial infections (p=0.003 and 0.0006, respectively) and in nine patients receiving high daily doses (2600 or 1800 mg/m2) of 5-FU (p=0.0001 and < 0.0001, respectively). In 25 out of 32 episodes (78%), plasma ammonium levels and mental status returned to normal within 2 days after adequate management. In conclusion, hyperammonemic encephalopathy can occur in patients receiving continuous infusion of 5-FU. Azotemia, body fluid insufficiency and bacterial infections were frequently found in these patients. It is therefore important to recognize this condition in patients receiving continuous infusion of 5-FU.

Adult↗

PubMed1999

Weekly 24-h infusion of high-dose 5-flurouracil and leucovorin in patients with advanced gastric cancer.

The effect of biochemical modulation of weekly high-dose 5-fluorouracil (5-FU) 24 h infusion by leucovorin (LV) in the treatment of 39 consecutive patients with advanced gastric cancer without prior chemotherapy from October 1996 to August 1997 was examined. There were 21 male and 18 female patients with a median age of 56 years. The regimen consisted of 5-FU 2600 mg/m2 and LV 150 mg administered by 24 h infusion weekly for 6 weeks followed by a 2 week break. The treatment was repeated every 8 weeks until disease progression, patient refusal or unacceptable toxicity. Placement of a central vascular device and a portable external infusion pump was required in all patients and was used for outpatient treatment. The response to treatment was evaluated every 8 weeks. A total of 395 chemotherapy treatments were given with a mean of 10 (2-24). This response rate was: 33% (12 of 36) partial response (PR) rate, 33% (12 of 36) stable disease (SD) and 33% (12 of 36) progressive disease (PD). In general, the toxicity was mild but two toxic deaths occurred, one due to neutropenic sepsis and the other due to hyperammonemia. The median time to progression was 4 months. The overall median survival was 7 months. The survivals of the PR, SD and PD were 12, 8 and 5 months, respectively. This regimen showed a modest activity against gastric cancer with acceptable toxicity. Weekly 24 h infusion of high-dose 5-FU with LV in an outpatient setting for patients with gastric cancer is feasible and deserves further study as a basis for combination therapy.

Adult↗

PubMed1999

Three-dimensional facial model reconstruction and plastic surgery simulation.

Facial model reconstruction and surgical simulation are essential to plastic surgery in today's medicine. Both can help surgeons to design appropriate repair plans and procedures prior to actual surgery. In this paper, we exploit a metamorphosis technique in our new design. First, using metamorphosis and vision techniques, we can establish three-dimensional facial models from a given photo. Second, we design several morphing operators, including augmentation, cutting, and lacerating. Experiments show that the proposed algorithms can successfully create acceptable facial models and generate realistically visual effects of surgical simulation.

Computer Simulation↗