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Biomedical subjects

M Lin

Publications and source records attributed to M Lin.

At least 163 records · Page 9Linked to original sources
PubMed1999

New management of malignant glaucoma by phacoemulsification with posterior chamber foldable intraocular lens implantation.

OBJECTIVE: To investigate the feasibility of phacoemulsification with posterior chamber foldable intraocular lens implantation in the management of malignant glaucoma. PATIENTS AND METHODS: Fourteen patients with malignant glaucoma diagnosed in the Department of Glaucoma were enrolled in the study. 12 patients developed malignant glaucoma after filtration surgery. 1 developed after peripheral iridectomy. 1 patient developed malignant glaucoma without any clear cause. Cataract phacoemulsification was performed. Posterior chamber intraocular foldable lens was implanted in 10 cases of patients. RESULTS: All 14 patients were cured with normal intraocular pressure, normal anterior chamber depth and increased visual acuity. CONCLUSION: Phacoemulsification with posterior chamber foldable intraocular lens implantation is a good alternative in treating malignant glaucoma.

Aged↗
PubMed1999

[Effect of N-methyl-D-aspartate and dexamethasone on apoptosis of rat cultured retinal ganglion cells].

PURPOSE: To investigate the effect of N-methyl-D-aspartate(NMDA) and Dexamethasone on cultured rat retinal ganglion cells (RGCS). METHODS: RGCs were obtained from 1-3 days old SD rats. In two groups, exposure of cocultured ganglion cells to N-methyl-D-aspartate (20-500 mumol/L) lasted for 24 hours. Apoptotic cells were identified by Hochest 33258 in one group; In another group, 0.4% Trypan blue dye was added. Cells excluding the dye were counted, and the survival rate of cells was determined by the ratio of the excluding cells in the experiment over in the control; Cocultured RGCs and purified RGCs were exposed to Dexamethasone(1 x 10(-4), 1 x 10(-5) and 1 x 10(-6) mol/L). After 24 hours, apoptotic cells were identified by Hochest33258. RESULT: Cocultured RGCs showed distinct morphological appearance of apoptotic cells when they were exposed to NMDA. The survival rate of cells was dose-related to the concentration of NMDA. Cocultured RGCs didn't show typical apoptotic appearance at 24 hours after exposure to Dexamethasone. But purified RGCs did so, even in the control group. CONCLUSION: NMDA has the effect of inducing cocultured RGCs apoptosis. Dexamethasone had no this effect on RGCs. Without additional neurotrophic factors, purified RGCs may become apoptotic cells when cultured in vitro for 24 hours.

Animals↗
PubMed1998

Diagnosis of bovine brucellosis using a homogeneous fluorescence polarization assay.

To evaluate the fluorescence polarization assay (FPA) for the serological diagnosis of bovine brucellosis, 118 sera from cattle which were culture positive for Brucella abortus, 1751 sera from cattle from premises containing cattle infected with B. abortus, 1222 sera from cattle vaccinated with B. abortus strain 19 and 1199 sera from cattle with no evidence of brucellosis were tested in Argentina, Chile, Mexico and in the American states of Iowa, Missouri and Texas. Initial determination of serological positivity and negativity was based upon reactivity in currently used serological tests, consisting of a rapid screening test, the rose-bengal or the buffered plate antigen tests, followed by a second serological test, the complement fixation test. Sensitivity of the FPA (sera from culture positive animals) ranged from 87.5% to 100%. Serological positivity of cattle from infected premises ranged from 65.5% to 99.0% while the % negative cattle in herds without evidence of brucellosis was between 94.9 and 100%. Of B. abortus strain 19 vaccinated cattle which were positive in at least one in-use serological tests, 88.2% were negative in the FPA. In contrast, previous Canadian studies, sensitivity values were 99.0% and 100% and the specificity in both cases was 100%. This discrepancy was probably due to the use of less well characterized sera in the current study.

Animals↗
PubMed1998

Expression of plasma phospholipid transfer protein mRNA in normal and emphysematous lungs and regulation by hypoxia.

The lung is the major site expressing plasma phospholipid transfer protein (PLTP) mRNA in humans and mice, suggesting that this protein might have an important role in maintaining normal function of this organ. In the lung of human collagenase transgenic mice, an emphysematous animal model, PLTP mRNA was 3-fold higher than in control mice. However, the mRNA in other tissues was not changed. To further assess the expression and function of PLTP, we measured PLTP mRNA level in lung tissue of two emphysematous patients and found that the mRNA was 4-fold higher than in control subjects. In situ hybridization on mouse lung suggested positive staining in alveolar type II epithelial cells. In addition, immortalized rat alveolar pre-type II epithelial cells and freshly isolated mature rat alveolar type II epithelial cells both highly expressed PLTP mRNA, and the former cells actively secreted PLTP activity into the medium. To examine the possible mechanisms leading to high levels of PLTP expression in vivo, we exposed the pre-type II cells to hypoxia and demonstrated induction of PLTP mRNA and a coordinate increase in secreted PLTP activity. Thus, the PLTP gene is highly expressed in alveolar type II epithelial cells and is induced during hypoxia and in emphysema. These observations suggest that a hypoxic stimulus occurring in emphysema may be a novel mechanism that contributes to enhanced expression of PLTP.

Animals↗
PubMed1998

Isotope-Filtered Affinity NMR

A double-editing pulse sequence has been developed that allows the direct observation of protein binding ligand(s) from a mixture of compounds. This technique should aid the discovery of lead pharmaceutical compounds. The proton NMR signals from protein and the nonbinding ligands are simultaneously eliminated using 13C isotope editing and PFG diffusion-edited NMR. This new experiment is demonstrated using 13C/15N-labeled stromelysin catalytic domain (SCD). Copyright 1998 Academic Press.

Journal Article↗
PubMed1998

Leptin in human pregnancy: the relationship with gestational hormones.

OBJECTIVES: The aims of the study were (1) to examine the relationship between leptin and placental hormones by measuring serial changes in serum levels of leptin during and after pregnancy and (2) to study the effects of several gestational hormones on leptin release from fully differentiated 3T3-L1 adipocyte cell cultures. STUDY DESIGN: Serum levels of leptin were measured throughout pregnancy and at 3 months post partum in 29 healthy women and were also measured in 18 healthy women at delivery by cesarean section and on postpartum day 3. In addition, 3T3-L1 mouse adipocytes were incubated for 24 hours in media containing various reproductive hormones and leptin production was measured. RESULTS: Serum leptin levels increased significantly (8.4 +/- 0.9 vs 13.5 +/- 1.5 ng/mL; P <.001) between the first 2 trimesters of pregnancy but not between the second and third trimesters. These changes in leptin did not correlate significantly with changes in body mass index. Leptin levels dropped significantly during the immediate postpartum period, from 34.1 +/- 4.9 at cesarean delivery to 7.3 +/- 1.4 ng/mL on postpartum day 3 (P <.001). Fasting insulin level did not correlate significantly with leptin level during pregnancy but did so during the postpartum period (r = 0.60; P <.05). Leptin secretion from 3T3-L1 adipocytes was increased significantly when cells were cultured with human chorionic gonadotropin (150%, P <.01) and also when they were cultured with estrogen (120%, P <.03). CONCLUSION: The data suggest that leptin production by adipose tissue is stimulated by several hormones of pregnancy, which may contribute to the increased leptin levels observed during gestation.

3T3 Cells↗
PubMed1998

Immunohematology in Taiwan.

There are major differences in the distribution of blood group antigens and antibodies between the different population groups of Taiwan and whites. As a result, standard Western pretransfusion testing procedures have been modified for use in Taiwan, resulting in great reductions in cost and labor. These differences, in addition to their influence on the clinical practise of transfusion medicine in Taiwan, are also important anthropologically, and it is hoped that more population groups in Asia can be investigated in the near future. Further DNA studies on the B3 phenotype, the MiIII phenotype, and the Lewis phenotypes among our different population groups are in progress and further interesting findings are awaited.

Antigens↗
PubMed1998

Improved free musculocutaneous flap survival with induction of heat shock protein.

The cellular response to a wide variety of stresses results in the synthesis of a family of stress response proteins termed heat shock proteins. Recent studies have demonstrated that heat shock proteins produced in response to an initial stress seem to protect against subsequent unrelated stresses. Importantly, hyperthermia-induced heat shock proteins provided protection from ischemia/reperfusion injury in several organ transplantation models. We hypothesized that free musculocutaneous flap survival could be improved by enhancing the flap's tolerance to relative ischemia by the prior induction of heat shock proteins. Accordingly, we determined the heat shock protein response in skin and muscle after systemic or local heating and examined the effect on free musculocutaneous flap survival in a rat model. Free musculocutaneous flaps incorporating thigh adductor muscles and a 2 x 6-cm2 skin paddle were transplanted to the ipsilateral groin in three groups of male Wistar rats. Systemically heated rats (n = 6) were anesthetized and incubated for 30 minutes at 42 degrees C 6 hours before free musculocutaneous tissue transfer. Locally heated rats (n = 6) were anesthetized, and their donor site anterior thigh was placed for 30 minutes on a heating block set at 44 degrees C 6 hours before free tissue transfer. Control rats (n = 5) did not have heating pretreatment but underwent identical anesthesia. Animals were sacrificed on postoperative day 3, at which time skin loss (cm2) and muscle viability, quantified by nitroblue tetrazolium staining time, were assessed in a blinded fashion. The skin and muscle from the free flap were analyzed for HSP72 mRNA and protein using quantitative Northern and Western blot techniques. All free musculocutaneous flaps were viable. However, the locally and systemically heated rats demonstrated a marked improvement of skin survival, which correlated with increased skin levels of HSP72. There were no differences in nitroblue tetrazolium muscle staining times or muscle levels of HSP72 among the three groups. These findings suggest that prior heat-induced heat shock proteins result in improvement in musculocutaneous flap survival, which may have direct clinical applications, especially in high-risk patients.

Animals↗
PubMed1998

Fetal sheep adrenal blood flow responses to hypoxemia after splanchnicotomy using fluorescent microspheres.

Adrenal gland blood flow (ABF) increases during hypoxemia in fetal sheep, but regulation of ABF is poorly understood. The purpose of this study was to determine the effects of splanchnic nerve section on fetal ABF responses to hypoxemia using the fluorescent microsphere (FM) technique. At 125 days of gestation, 14 unanesthetized fetal sheep [bilateral splanchnicotomy (Splx, n = 6) and control (Cont, n = 8)] were injected with FM before and at 60 min of N2-induced hypoxemia (approximately 40% decrease in fetal arterial PO2). Adrenal tissue and reference blood samples were digested and filtered, and FM dye was extracted for spectrometer analysis. Baseline whole, medullary, and cortical ABF for the Cont group were similar to published values using radioactive microspheres and did not differ from Splx values. Hypoxemia increased whole, medullary, and cortical ABF (mean +/- SE) from baseline for the Cont group by 281 +/- 35, 258 +/- 31, and 496 +/- 81% (P < 0.05). The increase for the Splx group was attenuated compared with the Cont group (P < 0.05) for whole and medullary ABF (139 +/- 27 and 43 +/- 27%) but not cortical ABF (326 +/- 91%). We conclude that 1) the FM technique is valid for measuring fetal ABF and 2) in fetal sheep the splanchnic nerve is not necessary to maintain basal ABF but plays an important role in regulating the hypoxemia-induced increase in ABF through the medullary, but not cortical, ABF response.

Adrenal Glands↗
PubMed1998

Reference typing report for complement receptor 1 (CR1).

A total of 100 Chinese blood donors (50 from Shen-Zhen and 50 from Taiwan) were studied by the participants in addition to 9 reference samples. A new nomenclature for the CR1 structural alleles was recommended by the participants which would use a numbering system, e.g. CR1*1. The structural allele frequencies in the Chinese were: CR1*1 (190 kD) 0.96, CR1*2 (220 kD) 0.03, CR1*3 (160 kD) 0.01 and CR1*4 (250 kD) 0.00. The HindIII expression polymorphism was also studied and the high expressing allele had a gene frequency of 0.71 while the low expressor gene frequency was 0.28. Erythrocyte copy numbers were quantified and compared between laboratories with good correlation (R = 0.55-0.88). The mean (+/- SD) erythrocyte copy number was 463 (+/- 229) in the Taiwan donors and 446 (+/- 207) in the Mainland Chinese.

Alleles↗
PubMed1998

Peanut lectin-binding sites and mucins in benign and malignant colorectal tissues associated with schistomatosis.

An immunohistochemical and histochemical comparative study was carried out in benign and malignant colorectal tissues with and without schistosomiasis. This included a quantitative determination of peanut lectin (PNA)-binding sites and proliferating cell nuclear antigen (PCNA) expression and histochemical detection of mucin changes. 133 cases were studied, including 70 cases of colorectal carcinoma associated with schistosomiasis (CCS) and 63 cases of colorectal carcinoma without schistosomiasis (CC). Significant differences were found in the type of mucin-containing carcinomas (MC) between CCS and CC. 65% of non-tumorous mucosa adjacent to MC of the CCS group expressed PNA-binding sites, significantly higher than those of the MC in the CC group (31%). The non-tumorous mucosa in cases of MC of the CCS group also showed a high percentage of sialomucin-predominant secretion (69%, vs 38% in MC of the CC group). Consistently, the presence of PNA-binding sites in MC tumors of the CCS group was increased, compared with that in the same subtype in the CC group (respectively 65% and 31% of strong positivity for PNA). However, no differences in expression of PNA and mucin changes were demonstrated in the surrounding mucosa and tumorous tissues of non-mucin-containing carcinomas (NMC) between CCS and CC. The expression of PCNA was not different between CCS and CC and their subtypes. Our findings suggest a close relationship between mucin-containing colorectal carcinomas and schistosomiasis japonica.

Colorectal Neoplasms↗
PubMed1998

Isolation of proteins from subacrosomal region of spermatozoa from a marsupial, the tammar wallaby (Macropus eugenii).

Recent studies indicate that subacrosomal proteins are necessary for the attachment of the acrosome onto the nucleus during sperm formation, and for the stability of the nuclear membrane during fertilization. For the first time, subacrosomal proteins have been isolated from a marsupial species, the tammar wallaby (Macropus eugenii), using a method developed in our laboratory. Whole ejaculated spermatozoa were fractionated into head and tail sections by ultrasonication to extract subacrosomal proteins. The heads (> 95% purity) were then isolated from tail sections using centrifugation with a three-step discontinuous sucrose gradient (35, 68 and 75% (w/v). The heads were treated with 0.1% (v/v) Triton X-100 which stripped off the acrosome, but not the subacrosomal proteins, from the head. The proteins were finally extracted by 100 mmol NaOH l-1. Four prominent subacrosomal polypeptides, with molecular masses of 45, 38, 33 and 29 kDa, were recognized from the SDS-PAGE gel. The localization of these polypeptides (particularly the 45 kDa polypeptide) was confirmed by fluorescent and immunogold labelling with polyclonal antibodies raised in mice against the obtained polypeptides. In wallaby testes, the 45 kDa polypeptide was detected as early as at the step 3 spermatid and was mainly associated with the membrane of the newly formed acrosome vesicle. This polypeptide was also found on the acrosomal membrane of all older spermatids. The 45 kDa polypeptide was found on the acrosomal region of the spermatozoa collected from the caput, corpus and cauda of the epididymis. The similarity of the sperm anatomy of the tammar wallaby with that of other marsupials, such as the brushtail possum, implies that this procedure could be applied effectively to other marsupial species with minor modification.

Animals↗
PubMed1998

Expression of human interleukin 12 (hIL-12) in insect cells.

Human interleukin-12(hIL-12) is a herterodimer cytokine, which consists of two disulfide-linked subunits, p40 and p35. This paper reports the expression of hIL-12 using the Baculovirus Expression System in insect cells. First, we constructed two expression vectors pVL1392-hp40 and pVL1393-hp35, and then they were used to co-transfect the insect cells (Sf9) separately with linearized polyhedrosis virus genomic DNA. Two kinds of recombinant viruses AcNPV-hp40 and AcNPV-hp35 were visually screened out. Biological activity of the recombinant hIL-12 (rhIL-12) was detected in the conditioned medium using proliferation assay of PHA-activated human lymphocytes and the expression level was about 1.5 approximately 2 microg/10(6) cells. The results of real-time Biomolecular Interaction Analysis (BIA) and Northern blot demonstrated that the subunits of rhIL-12, hp35, and hp40 were expressed successfully in the insect cells. The apparent molecular weights of rhIL-12 and hp40 homodimer were 76 kDa and 92 kDa under non-reducing conditions of Western blot, respectively. The recombinant hp40 can significantly inhibit the biological activity of hIL-12.

Animals↗
PubMed1998

[Study on MDM2 and p53 gene proteins expression on acute leukemic cells and its correlation with chemotherapeutic efficacy].

OBJECTIVE: To explore MDM2 and p53 gene proteins expression on human acute leukemia (AL) cells and their predictive value for chemotherapeutic efficacy. METHODS: MDM2 and p53 gene proteins expression was assayed by immunohistochemical staining. RESULTS: 1. The expression rates of MDM2 and p53 gene proteins were 71.7% and 21.7% respectively in 46 AL patients. The rates were slightly higher in relapse/refractory AL than in previously untreated AL; there was no difference among AL subtypes. 2. MDM2+ and p53- accounted for 67.4%, while the uniform expression of MDM2 and p53 15.2% (P < 0.01). 3. The marrow complete remission (CR) rate (69.2%) of MDM2- patients was higher than that (33.3%) of MDM2+ patients (P < 0.05). 4. Two of 4 patients with MDM2+++ gained CR and then MDM2 turned negative. CONCLUSION: MDM2 gene protein was negatively related with p53 gene protein in AL cells. Different expression patterns of the two gene proteins could influence the therapeutic efficacy, and combined detection of the two may be used as a prognostic parameter for AL patients.

Adolescent↗
PubMed1998

[Research on the separation behavior of acidic drugs in capillary electrophoresis with reversed direction of electroosmotic flow].

The separation behavior of acidic drugs in capillary electrophoresis with reversal of electroosmotic flow was investigated systematically. Acetylsalicylic acid and its related compound salicylic acid were employed as objective drugs. The cationic surfactant cetyltrimethylammonium bromide (CTAB) was used as reversed reagent for electroosmotic flow. The experimental conditions, such as, cationic surfactant concentration, buffer pH and organic additives, which affected migration time, peak shape and column efficiency, were studied in detail. The experimental results indicated that high speed analysis could be achieved in the capillary electrophoresis with reversed electroosmotic flow induced by cationic surfactant when acidic drugs were analysed. The poor peak shape and low column efficiency caused by the interactions of CTAB with acidic anions would be improved by adding proper organic additive, such as, beta-cyclodextrin or acetonitrile.

Aspirin↗
PubMed1998

[The construction of Alcaligenes faecalis ntrC-lacZ fusion gene and its expression during association with rice roots].

A broad host range vector pLA2917 containing ntrC gene or ntrC-lacZ fusion were constructed, namely pLAC1 and pLAC2. The plasmids pLAC1 and pLAC2 were introduced into A. faecalis wild type strain A1501 by conjugation, subsequently to abtain A15C1 and A15C2. The expression and regulation of ntrC gene of A. faecalis associated with rice roots was investigated under the condition of the associative nitrogen fixation using X-Gal decoration method, micrograph and ntrC partially deletion mutant. The blue precipitation was strongly existed in parenchyma cells as well as in the lateral root primordial. It showed that ntrC gene could express at much higher level in these sites. In the presence of ammonia, the number of multi-copy ntrC conjugatants colonized on surface of rice roots is higher than that of wild type A1501, and the colonization of ntrC mutant is weakest among these three strains. This provided an evidence that ntrC gene might be involved in procedure of colonization of A. faecalis to rice roots.

Alcaligenes↗