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Biomedical subjects

G Ling

Publications and source records attributed to G Ling.

34 records · Page 2Linked to original sources
PubMed1999

[Detection of apoptosis exposed to 10-hydroxycamptothecin in T24 human urinary bladder cancer cells].

OBJECTIVE: To study whether 10-hydroxycamptothecin (HPT) can induce apoptosis in bladder cancer cell and establish methods for detecting apoptotic cells. METHODS: Human urinary bladder cancer cell line (T24) was exposed in vitro to different concentrations of 10-hydroxycamptothein for various lengths of time. Flow cytometry, Hochest 33258 and Hematoxylin staining were used to determine the induction of apoptosis after use of HPT. DNA gel analysis was also carried out to detect DNA fragmentation. RESULTS: Cell shrinage, nuclear fragmentation and condensed chromosomes showed that apoptosis can be induced by HPT within the concentration of 0.01 - 10 microg/ml. The flow cytometry analysis showed that the percentage of apoptotic cells were related to the concentration and the time of induction. T24 cell line exposed to HPT experienced internucleosomal DNA fragmentation by producing a typical ladder pattern on agarose gel electrophoresis. The detection of minimum exposure time for HPT-induced apoptosis in T24 cells showed that 3 hours of exposure to HPT were enough to trigger internucleosomal DNA fragmentation. Compared to Hochest 33258 staining, Hematoxylin staining was more easy, rapid and accurate to detect apoptosis. CONCLUSIONS: The induction of apoptosis exposed to HPT in T24 human urinary bladder cancer cells is a good model for further studying urinary bladder cancer. Hematoxylin staining is a useful method for detecting apoptosis.

Antineoplastic Agents, Phytogenic↗
PubMed1998

Clones of normal keratinocytes and a variety of simultaneously present epidermal neoplastic lesions contain a multitude of p53 gene mutations in a xeroderma pigmentosum patient.

A patient with xeroderma pigmentosum group C was extensively examined for mutations in the p53 gene in normal skin exposed to varying degrees of sunlight and in excisional biopsies of basal cell cancer, squamous cell cancer, and squamous cell dysplasia. Seventy-three samples were analyzed by microdissection of small cell clusters, followed by PCR and direct DNA sequencing. In skin taken from areas that most likely had never been exposed to the sun, no mutations were found. However, in skin exposed to the sun, we observed a multitude of mutations in the p53 gene. UV light-induced mutations were found in all types of lesions, as well as in clusters of morphologically normal epidermal cells. Twenty-nine distinct mutations were found in exons 5-8, all missense or nonsense, of which 27 (93%) were UV-specific C --> T or CC --> TT transitions at dipyrimidine sites of the nontranscribed strand. Two types of normal skin areas containing p53 mutations were observed: areas that stain strongly with p53 antibody (p53 patches) and those that do not stain. Because no silent or intron mutations were found in these cell clusters, the alterations in the p53 gene of morphologically normal cells are likely to have resulted in a selective growth advantage. The poor correlation between mutations and morphological phenotypes demonstrates that p53 mutations alone do not determine the phenotypes observed.

Adolescent↗
PubMed1998

Lactated Ringer's solution resuscitation causes neutrophil activation after hemorrhagic shock.

PURPOSE: To determine the degree of neutrophil activation caused by hemorrhagic shock and resuscitation. METHODS: Awake swine underwent 15-minute 40% blood volume hemorrhage, and a 1-hour shock period, followed by resuscitation with: group I, lactated Ringer's solution (LR); group II, shed blood; and group III, 7.5% hypertonic saline (HTS). Group IV underwent sham hemorrhage and LR infusion. Neutrophil activation was measured in whole blood using flow cytometry to detect intracellular superoxide burst activity. RESULTS: Neutrophil activation increased significantly immediately after hemorrhage, but it was greatest after resuscitation with LR (group I, 273 vs. 102%; p < 0.05). Animals that received shed blood (group II) and HTS (group III) had neutrophil activity return to baseline state after resuscitation. Group IV animals had an increase in neutrophil activation (259 vs. 129%; p < 0.05). CONCLUSION: Neutrophil activation occurring after LR resuscitation and LR infusion without hemorrhage, but not after resuscitation with shed blood or HTS, suggests that the neutrophil activation may be caused by LR and not by reperfusion.

Animals↗
PubMed1998

[Rapid determination of creatinine in urine by capillary electrophoresis in a multiple injection mode].

The level of urinary creatinine in clinic diagnosis is one of the useful index of renal function, and is often used as a reference of some biochemical substance determined in random urine. In this paper, a rapid multiple-injection capillary electrophoresis(CE) method for the determination of urinary creatinine is reported. A 36 cm x 50 microns coated capillary, a phosphoric acid buffer(0.1 mol/L, pH 2.5)and UV-detector at 200 nm wavelength were used in this method. In comparing with single injection for five samples, the analysis time of five successive injections can save 20 min. By use of pyridine as internal standard, the correlation between the concentrations of creatinine and the corresponding peak height ratios of creatinine and pyridine is good(r = 0.9996), and the assay precision is acceptable. We also compared the CE method with the bio-analyser(Jeffe' kinetic), and the results showed a satisfactory correlation (r = 0.9773, n = 12) and a shorter analysis time.

Creatinine↗
PubMed1997

Migration of medial smooth muscle cells to the intima after balloon injury.

Migration to the intima and other responses of M-SMC in the rat carotid artery and abdominal aorta after balloon injury were investigated in vivo. Migration occurred intensively between the second and fifth days after injury. About 80% of the cells were in the G1 and S phases of the cell cycle. The majority of the migrating cells were therefore simultaneously proliferating. Positive values of 42.3%, 48.9%, 44.4%, and 32.8% of the migrating cells on the fifth day in the carotid artery for PDGF-B, elastase III B, MMP-I, and MMP-9, were observed, respectively. Many of the cells expressed messages of PDGF-A and elastases II and III B by in situ hybridization. Fine structures of the migrating cells were characterized as a synthetic phenotype of the smooth muscle cell with reduced attachment to their surrounding ECM. A biphasic proliferative response of the M-SMC appeared on the second and fifth days. Migration occurred correspondingly in the proliferative period. The populations of M-SMC positive in immunostainings for PDGFs, their receptors, elastase III B, and MMP-1 and MMP-9 also increased biphasically, around 12 h and five days after the injury. The results of these studies suggest that the migrating cells were proliferative and synthesizing PDGFs, elastases, and collagenases.

Angioplasty, Balloon↗
PubMed1997

Genomic analysis of single cells from human basal cell cancer using laser-assisted capture microscopy.

In this study, we show that direct mutational analysis of genomic DNA can be performed on single somatic cells extracted from a frozen, immunohistochemically stained tissue section using laser-assisted capture microscopy. Eighty-nine single tumor cells were separately dissected from one case of human basal cell cancer (BCC) and p53 mutations were analyzed by direct semi-automated sequencing of PCR fragments. Amplification was obtained for at least one of the two analyzed exons from approximately 50% of the single tumor cells. Identical p53 mutations were found in widely spread areas of the tumor, suggesting a clonal proliferation originating from one cell. Interestingly, comparison between results of immunohistochemistry and genetic analysis of the single cells revealed the same p53 mutations irrespective of the p53 immunoreactivity. We propose that this approach has a great potential to allow investigation of genotypic differences in single cells and more specifically to resolve important and fundamental questions determining cancer heterogeneity.

Aged↗
PubMed1997

[Apoptosis of nasopharyngeal carcinoma cells induced by topoisomerase I inhibitor].

PURPOSE: To determine if the topoisomerase I inhibitor Camptothecin (CPT) can induce apoptosis in vitro in a human nasopharyngeal carcinoma (NPC) cell line with low differentiation (CNE-2Z). METHODS: The light microscopy, flow cytometry and agarose gel electrophoresis were used to examine the morphological changes, cell cycle distribution, hypodiploid cells and DNA fragmentation. RESULTS: After exposure to CPT for a certain period, CNE-2Z cells underwent obvious morphological changes with characteristics of apoptosis such as decrease in cell volumes condensation of chromatin and the formation of apoptotic bodies. Flow cytometry (FCM) test showed that when CNE-2Z cells were treated with 2-10 mumol/L CPT for 12 or 24 hours, hypodiploid cells accounted for 30% and 50% respectively. Cell cycle analysis by FCM revealed that changes in CNE-2Z cell cycle distribution were apparent 24 hours after treatment with various doses of CPT, showing no obvious dose-dependent relationship. Compared with controls, the percentage of cells in G2/M phase decreased markedly while those in G1 and S phases increased moderately. CONCLUSION: The results demonstrated that DNA topoisomerase I inhibitor Camptothecin can induce apoptosis in CNE-2Z cells in vitro.

Antineoplastic Agents, Phytogenic↗
PubMed1997

[Determination of human urinary pseudouridine by high performance capillary electrophoresis].

Pseudouridine, mainly as a degradation product of transfer ribonucleic acid, has been shown to be excreted in abnormal amounts in the urine of patients with cancer and can be used as one of the potentially valuable tumor markers. In this paper, a method for the rapid determination of human urinary pseudouridine by HPCE is reported. We used a 24 cm x 25 microm i.d. coated capillary and a borate buffer solution (0.1 mol/L, pH 8.6), and set the UV detection wavelength at 200 nm. In this experiment, pseudouridine can be separated completely with uridine and anti-tumor drugs (5-fluouridine and methetrexation) and other endogenous substances in urine within 4 minutes. Assay precision was determined for concentrations of 50 micromol/L and 200 micromol/L as 2.38% and 1.92% for within-day CV, 3.7% and 2.4% for between-day CV respectively. Sulfosalicylic acid was used as internal standard. Linearity, between the concentrations of pseudouridine and the corresponding peak height or area ratios of pseudouridine and the internal standard, was demonstrated in the 6.25-200 micromol/L range (r>0.9990). The detection limit of concentration for pseudouridine was 4 micromol/L. This method, with simple sample preparation, good assay precision, lower cost and full-automation, is an effective means for the assessment of pseudouridine in clinical application.

Electrophoresis, Capillary↗
PubMed1997

Analysis of apoptosis during hair follicle regression (catagen)

Keratinocyte apoptosis is a central element in the regulation of hair follicle regression (catagen), yet the exact location and the control of follicular keratinocyte apoptosis remain obscure. To generate an "apoptomap" of the hair follicle, we have studied selected apoptosis-associated parameters in the C57BL/6 mouse model for hair research during normal and pharmacologically manipulated, pathological catagen development. As assessed by terminal deoxynucleotide transferase dUTP fluorescein nick end-labeling (TUNEL) stain, apoptotic cells not only appeared in the regressing proximal follicle epithelium but, surprisingly, were also seen in the central inner root sheath, in the bulge/isthmus region, and in the secondary germ, but never in the dermal papilla. These apoptosis hot spots during catagen development correlated largely with a down-regulation of the Bcl-2/Bax ratio but only poorly with the expression patterns of interleukin-1beta converting enzyme, p55TNFR, and Fas/Apo-1 immunoreactivity. Instead, a higher correlation was found with p75NTR expression. During cyclophosphamide-induced follicle dystrophy and alopecia, massive keratinocyte apoptosis occurred in the entire proximal hair bulb, except in the dermal papilla, despite a strong up-regulation of Bax and p75NTR immunoreactivity. Selected receptors of the tumor necrosis factor/nerve growth factor family and members of the Bcl-2 family may also play a key role in the control of follicular keratinocyte apoptosis in situ.

Administration, Topical↗
PubMed1981

Effects of ethanol dependence on chronic spinal rats monitored by spontaneous hind leg movements.

Physical dependence on ethanol was produced in rats whose spinal cords were transected at midthoracic level ("chronic spinal" rats) 2 months before chronic ethanol administration. Both intact and chronic spinal rats were treated with a light anesthetic dose of ethanol three times a day for 12 to 14 days and then abruptly withdrawn. All ethanol-treated animals exhibited severe withdrawal signs, including spontaneous withdrawal convulsions and death in over 60% of animals. In addition, ethanol-treated chronic spinal rats developed characteristic spontaneous hind leg movements (SLMs) during withdrawal. The time course, onset, peak and disappearance of these SLMs correlated well with other ethanol withdrawal signs. Cross dependence studies showed that ethanol, pentobarbital and barbital, diazepam and chlordiazepoxide, but not morphine, suppressed SLMs when drugs were administered at the peak intensity of SLM activities, while the intensity of behavioral withdrawal signs was also attenuated.

Alcoholism↗