Biomedical subjects

W Tong

Publications and source records attributed to W Tong.

At least 55 records · Page 3Linked to original sources

PubMed1999

Epidermal and hepatocyte growth factors stimulate chemotaxis in an intestinal epithelial cell line.

The migration of intestinal cells is important in the development and maintenance of normal epithelium, in a process that may be regulated by growth factors and cytokines. Although a number of growth factor receptors are expressed by intestinal cells, little progress has been made toward assignment of functional roles for these ligand-receptor systems. This study compares several growth factors and cytokines for their chemoattraction of the mouse small intestinal epithelial cell line. Epidermal and hepatocyte growth factors stimulated a rapid 30-fold chemotaxis of cells with delayed threefold migration toward transforming growth factor-beta1. Despite stimulating proliferation, keratinocyte, fibroblast, or insulin-like growth factors did not stimulate directed migration. Chemotaxis required tyrosine kinase and phosphatidylinositol phospholipase C activities but not protein kinase C or mitogen-activated protein kinase activity. These findings suggest that the repertoire of growth factors capable of regulating directed intestinal epithelial cell migration is limited and that a divergence exists in the signal transduction pathways for directed vs. nondirected migration.

Animals↗

PubMed1999

Toxicology and pharmacokinetics of intravesical gemcitabine: a preclinical study in dogs.

More active and well-tolerated agents are needed for the treatment of superficial bladder cancer. This study investigated intravesical gemcitabine to establish the toxicology and pharmacokinetics necessary for clinical trials. Beagle dogs (in groups of 2; n = 6) received 100 mg, 350 mg, or 1 g of drug by intravesical administration on alternate days three times/week for 4 weeks. Animals were observed for clinical signs of toxicity; gemcitabine levels and peripheral blood counts were taken three times weekly. The dogs were euthanized, and a full necropsy was performed at days 1 and 14 after the last dose. Intravesical gemcitabine was given at 100 mg (n = 2), 350 mg (equivalent to the 1000 mg/m2 human dose; n = 3), and 3.5 g (n = 1). i.v. gemcitabine was given at 350 mg (n = 2). Plasma samples drawn at time points up to 8 h were analyzed for systemic absorption and clearance of drug. Doses of 100 and 350 mg were well tolerated with no clinical side effects. Necropsies revealed normal bone marrow cellularity and normal bladder histology. At 1 g, signs of severe clinical toxicity were evident, and after only three doses, necropsies demonstrated severe bone marrow hypoplasia, cystitis, and intestinal necrosis. At all intravesical doses, significant systemic absorption was seen. The T1/2 (+/- SD) for intravesical and i.v. administration of 350 mg was 328 (+/-6.8) min and 99.3 (+/-5.2) min, respectively (P<0.001). Intravesical gemcitabine is well tolerated and has no direct bladder toxicity at doses up to 1000 mg/m2. Higher doses result in gastrointestinal, bladder, and bone marrow toxicity.

Absorption↗

PubMed1999

Development of a universal immunoenzyme quantitative assay for detecting amplified products of nucleic acid and its preliminary application in hepatitis C virus.

OBJECTIVE: To develop a universal quantitative immunoenzyme assay (EIA) for detecting amplified products of nucleic acid and its application in hepatitis C virus (HCV). METHODS: The appropriate cycle number of amplification was selected to stop polymerase chain reaction (PCR) before the "plateau stage". At the same time, primers HCV (3) of the second PCR were modified with biotin so that the amplified products were labeled. The products were diluted and subsequently added to the streptavidin-coated wells, and the biotinylated products were captured, followed by denaturation of NaOH, and non-biotinylated strands were removed. Hybridization was performed by adding the specific probe labeled with fluorescein. Finally antifluorescein horse radish peroxidase (HRP) conjugates were added, after washing, 3, 3', 5, 5',-tetramethylbenzidine (TMB) was added to the wells and then measured on a microplate reader. RESULTS: EIA detection of amplified products of HCV showed that this assay was rapid, sensitive, specific and accurate. Correlation between the initial number of viral template and the EIA of amplified products was good. We also prospectively investigated the response to interferon in five patients with HCV coinfection. Results showed that this assay could be used as a guidance to the clinical therapy in directing the use of antiviral drugs. CONCLUSIONS: This assay could be widely used as a universal technique for the quantitative detection of amplified products of all nucleic acid (such as virus, bacterium) and other human genes (such as HLA B27), it has vast vistas.

Hepacivirus↗

PubMed1999

[Atypical intrathoracic sarcoidosis: a report of 21 cases].

OBJECTIVE: To improve the recognition of atypical intrathoracic sarcoidosis. METHODS: The clinical data of 21 cases with atypical intrathoracic sarcoidosis were analyzed retrospectively. All the cases had pathological examination data. RESULTS: The manifestations of atypical intrathoracic sarcoidosis might be as follows: intrapulmonary pathological changes including solitary nodular shadow, atelectasis, unilateral lung consolidation, bilateral lung consolidation and bilateral pulmonary miliary nodes; simple mediastinal lymph node lesion including mediastinal tumor, mediastinal lymph node enlargement plus unilateral pulmonary hilar lymph node enlargement and simple mediastinal lymph node enlargement; pleural lesion including hydropneumothorax and pleural thickening; pulmonary hilar lesion including unilateral pulmonary hilar lymph node enlargement plus mediastinal lymph node enlargement and bilateral pulmonary hilar lymph node enlargement and calcification. CONCLUSION: The clinical manifestations of atypical intrathoracic sarcoidosis are variable. The establishment of the diagnosis cannot be based on image examination alone. With sufficient knowledge of the clinical manifestations of sarcoidosis and other testing methods, the diagnosis can be made correctly.

Adolescent↗

PubMed1999

[Slow transit constipation treated by surgery: analysis of 17 cases].

OBJECTIVE: To explore the operative indications, prognosis, and possible pathogenic factors of slow transit constipation (STC). METHODS: 17 cases with STC who had undergone colectomy were analysed. RESULTS: Bowel movement frequency was once per 4 to 14 days in all of the patients, who had had long-term laxative abuse. Delayed colonic transit was demonstrated in all patients, 82.4% of them were accompanied by outlet obstructive constipation (OOC) and 50% showed abnormal sex hormones. Reduced numbers of argyrophilic neurons and vacuolar degeneration of axons were demonstrated at the myenteric plexus pathologically. Three patients had adhesive ileus postoperatively and one patient suffered from difficult evacuation again 5 years after the operation. CONCLUSIONS: Colectomy is highly effective in alleviating symptoms in patients with STC, and pelvic floor disorder of OOC should be treated simultaneously.

Adolescent↗

PubMed1998

Derivation of a pharmacophore model for anandamide using constrained conformational searching and comparative molecular field analysis.

Constrained molecular dynamics simulations on anandamide, together with a systematic distance comparison search, have revealed a specific low-energy conformer whose spatial disposition of the pharmacophoric elements closely matches that of HHC. This conformer enables near superposition of the following: (1) the oxygen of the carboxyamide and the phenolic hydroxyl group of HHC, (2) the hydroxyl group of the ethanol and the cyclohexyl hydroxyl group of HHC, (3) the alkyl tail and the lipophilic side chain of HHC, and (4) the polyolefin loop and the tricyclic ring structure of HHC. The close matching of common pharmacophoric elements of anandamide with HHC offers persuasive evidence of the biological relevance of this conformer. The proposed pharmacophore model was capable of discriminating between structurally related compounds exhibiting different pharmacological potency for the CB1 cannabinoid receptor, i.e., anandamide and N-(2-hydroxyethyl)prostaglandinamide. Furthermore, a 3D-QSAR model was derived using CoMFA for a training set of 29 classical and nonclassical analogues which rationalized the binding affinity in terms of steric and electrostatic properties and, more importantly, which predicted the potency of anandamide in excellent agreement with experimental data. The ABC tricyclic HU-210/HU-211 and ACD tricyclic CP55,243/CP55,244 enantiomeric pairs were employed as test compounds to validate the present CoMFA model. For each enantiomeric pair, the CoMFA-predicted log Ki values correctly identified that enantiomer exhibiting the higher affinity for the receptor.

Arachidonic Acids↗

PubMed1998

Laser-induced native fluorescence (LINF) imaging of serotonin depletion in depolarized neurons.

Since certain neurotransmitters exhibit native fluorescence we can monitor this property to disclose intracellular changes that result from neurotransmitter release. Isolated Retzius neurons of the leech are known to release serotonin (5-HT) during depolarization. Using intensified CCD technology coupled with UV laser (305 nm) excitation we observed depolarization and calcium-dependent reductions in native fluorescence in the axon, as well as in the cortex of the cell body. When taken together with data obtained from single-cell capillary electrophoresis, we demonstrate that this laser-induced native fluorescence can be reliably used to study spatial and temporal changes in intracellular transmitter content that accompany calcium-dependent secretion.

Animals↗

PubMed1998

Studies on diffusion maximum in x-ray diffraction patterns of plasma-sprayed hydroxyapatite coatings.

Study of an amorphous phase in plasma-sprayed hydroxyapatite (HA) coatings is important owing to its unique characteristics and nonnegligible amount of the amorphous phase compared to crystalline HA. However, little is known about the component parts of an amorphous phase. It is known that amorphous phase usually appears as the diffusion maximum (Dmax) in X-ray diffraction (XRD) patterns. Analyzing Dmax, including the position (Pmax) and area of Dmax, we can indicate the component parts of an amorphous phase and their transitions. In this study, the variation of Dmax in XRD patterns of the coatings during plasma spraying, in postheating, and in dissolving in vitro was studied with the aid of XRD. It was found that component parts of the amorphous phase in the coating varied with increasing thickness, consisting of two part represented by Dmax1, located between 29.4 and 29.8 degrees (2 theta), and Dmax2, located between 31.0 and 31.4 degrees (2 theta). It was concluded that Dmax3, located between 32.0 and 32.4 degrees (2 theta), should be referred to as nanocrystals of HA. In addition, the particle size of the starting powder may affect the component parts of the amorphous phase in the coating in addition to thickness. With vacuum heating (650 degrees C) and water vapor treatment at a low temperature (125 degrees C) in a saturated vaporic atmosphere, transition of the amorphous components was not as efficient as that at 490 degrees C with water vapor. The reason might be that the amorphous-to-crystalline HA conversion is dependent on both temperature and water vapor pressure. It was found that amorphous components were transformed completely into crystalline HA after heating at 490 degrees C with a partial water vapor pressure of 0.01 MPa for 2 h. It was concluded that the unstable amorphous components (Dmax1, Dmax2) converted into more stable nanocrystals of HA (Dmax3). Degradation in vitro showed that Dmax3 was more stable than Dmax1 and Dmax2. It was concluded that nucleation of apatite in vitro should be attributed to nanocrystals of HA (Dmax3) except for the amorphous components. It is recommended that the optimal phasic contents of the plasma-sprayed HA coating be mainly composed of crystalline HA and nanocrystals of HA (Dmax3) in terms of the stability and biocompatibility of the coating.

Air↗

PubMed1998

Characterization of Y122F R2 of Escherichia coli ribonucleotide reductase by time-resolved physical biochemical methods and X-ray crystallography.

Ribonucleotide reductase (RNR) from Escherichia coli catalyzes the conversion of ribonucleotides to deoxyribonucleotides. It is composed of two homodimeric subunits, R1 and R2. R2 contains the diferric-tyrosyl radical cofactor essential for the nucleotide reduction process. The in vitro mechanism of assembly of this cluster starting with apo R2 or with a diferrous form of R2 has been examined by time-resolved physical biochemical methods. An intermediate, Fe3+/Fe4+ cluster (intermediate X), has been identified that is thought to be directly involved in the oxidation of Y122 to the tyrosyl radical (*Y122). An R2 mutant in which phenylalanine has replaced Y122 has been used to accumulate intermediate X at sufficient levels that it can be studied using a variety of spectroscopic methods. The details of the reconstitution of the apo and diferrous forms of Y122F R2 have been examined by stopped-flow UV/vis spectroscopy and by rapid freeze quench electron paramagnetic resonance, and Mössbauer spectroscopies. In addition the structure of this mutant, crystallized at pH 7.6 in the absence of mercury, at 2.46 A resolution has been determined. These studies suggest that Y122F R2 is an appropriate model for the examination of intermediate X in the assembly process. Studies with two mutants, Y356F and double mutant Y356F and Y122F R2, are interpreted in terms of the possible role of Y356 in the putative electron transfer reaction between the R1 and R2 subunits of this RNR.

Amino Acid Substitution↗

PubMed1998

Intraocular concentrations of chemotherapeutic agents after systemic or local administration.

OBJECTIVES: To investigate the concentrations of carboplatin and etoposide achieved in the aqueous and vitreous humors after intravenous infusion in nonhuman primates, and to investigate whether local administration of carboplatin might result in higher concentrations in the vitreous humor. METHODS: Macaca fascicularis primates were treated with 1 of 3 regimens: (1) intravenous carboplatin (18.7 mg/kg), etoposide (5 mg/kg), and vincristine sulfate (0.05 mg/kg), (2) peribulbar carboplatin (10 mg/mL), or (3) episcleral balloon carboplatin (10 mg/mL). Concentrations of chemotherapeutic agents were measured in the plasma and in the aqueous and vitreous humors. RESULTS: No measurable amount of etoposide was detected in the aqueous or vitreous humor after intravenous administration. Mean measured peak vitreous concentration of carboplatin after intravenous administration was 0.31 microg/mL, which was 1% of the peak plasma value. Mean measured peak vitreous concentrations of carboplatin after peribulbar or episcleral balloon administration were 2.38 microg/mL and 2.95 microg/mL, respectively, which represent 7.68- and 9.52-fold increases over the concentration achieved after intravenous administration. No serious toxic effect was observed in any animal. CONCLUSIONS: Peribulbar and episcleral balloon administration of carboplatin seemed to be safe and resulted in higher vitreous concentrations than intravenous administration in this model. These results suggest that these alternate routes of delivery should be explored in children with vitreous seeding of retinoblastoma.

Absorption↗

PubMed1998

Dose-dense therapy with weekly 1-hour paclitaxel infusions in the treatment of metastatic breast cancer.

PURPOSE: To evaluate the efficacy and toxicity of paclitaxel administered as a 1-hour infusion on weekly basis, without interruption, to patients with metastatic breast cancer who had received prior therapy. PATIENTS AND METHODS: Thirty patients with metastatic breast cancer received sustained weekly paclitaxel therapy at an initial dose of 100 mg/m2 until disease progression. Prior therapy included adjuvant only (n=17), metastatic only (n=7), or both (n=6). Eighteen patients had received prior anthracycline therapy, 12 of whom had demonstrated progression of disease within 12 months of it. All patients were assessable for efficacy; 29 patients were assessable for toxicity. Pharmacokinetic studies of paclitaxel were also performed. RESULTS: A total of 469 weekly paclitaxel infusions were administered to 30 patients (median, 14 infusions/patient). The median delivered dose-intensity was 91 mg/m2/wk (range, 80 to 108). The overall response rate was 53% (95% confidence interval [CI], 34% to 72%), with 10% complete responses (CRs) and 43% partial responses (PRs). Median response duration was 7.5 months (range, 2 to 11+). Responses were observed in nine of 18 (50%) patients with prior anthracycline therapy, including six of 12 (50%) with disease progression on anthracycline within 1 year (three of four within 6 months). Therapy was well tolerated and remarkable for a lack of overall and cumulative myelosuppression. Grade 3/4 neutropenia occurred in four patients; febrile neutropenia was not observed. Peripheral neuropathy prohibited dose escalation above 100 mg/m2, and grade 3 neuropathy was observed in two of 21 patients at < or = 100 mg/m2. CONCLUSION: Weekly paclitaxel therapy is active and well tolerated in patients with metastatic breast cancer. Weekly therapy should be considered as a current clinical option for these patients and should be incorporated into future comparative clinical trials.

Adult↗

PubMed1998

[Study on HSP70, 90 mRNA gene expression in peripheral blood mononuclear cells with steroid-resistant asthmatics].

OBJECTIVE: To investigate the role of heat shock protein(HSP) 70, 90 alpha, 90 beta mRNA on the pathogenesis of steroid-resistant(SR) asthma. METHOD: 9 SR asthmadics 16 steroid sensitive (SS) asthmatics and 10 normal healthy volunteers were studied. With reverse transcription-polymerase chain reaction(RT-PCR), the expression of hsp70, 90 alpha, 90 beta mRNA were detected in peripheral blood mononuclear cell(PMBC) from normal volunteers and SR. steroid-sensitive(SS) asthmatics. Inhibition of PHA-induced lymphocyte proliferation by dexamethasones (Dex) was investigated using lymphocyte proliferation assay. RESULT: There were no expression of hsp70mRNA in PMBC of normal volunteers; the levels of expression of hsp70, 90 alpha, 90 beta mRNA in PBMC of SR asthmatics (70 = 2.95 +/- 1.12, 90 alpha = 2.17 +/- 0.89, 90 beta = 2.22 +/- 0.83) were significantly higher than SS asthmatics (70 = 0.23 +/- 0.09, 90 alpha = 1.07 +/- 0.39, 90 beta = 0.94 +/- 0.32) (P < 0.01) and normal volunteers (70 = 0, 90 alpha = 0.45 +/- 0.19, 90 beta = 0.32 +/- 0.15) (P < 0.01); There were significantly positive correlation between the degree of inhibition by Dex(10(-7) mol/L) of SR, SS asthmatics of proliferation of T lymphocytes and the expression of hsp70, 90 alpha, 90 beta mRNA in PMBC(P < 0.01). CONCLUSION: There were expression of hsp70, 90 alpha, 90 beta gene in PMBC from SR asthmatics, but increased with worsening of inflammation and prolonging of the duration of disease. The more hsp 90 gene expression, the less T lymphocytes were inhibited by Dex.

Adult↗

PubMed1998

The absence of p27Kip1, an inhibitor of G1 cyclin-dependent kinases, uncouples differentiation and growth arrest during the granulosa->luteal transition.

The involvement of cyclin-dependent kinase inhibitors in differentiation remains unclear: are the roles of cyclin-dependent kinase inhibitors restricted to cell cycle arrest; or also required for completion of the differentiation program; or both? Here, we report that differentiation of luteal cells can be uncoupled from growth arrest in p27-deficient mice. In these mice, female-specific infertility correlates with a failure of embryos to implant at embryonic day 4.5. We show by ovarian transplant and hormone reconstitution experiments that failure to regulate luteal cell estradiol is one physiological mechanism for infertility in these mice. This failure is not due to a failure of p27-deficient granulosa cells to differentiate after hormonal stimulation; P450scc, a marker for luteal progesterone biosynthesis, is expressed and granulosa cell-specific cyclin D2 expression is reduced. However, unlike their wild-type counterparts, p27-deficient luteal cells continue to proliferate for up to 3.5 days after hormonal stimulation. By day 5.5, however, these cells withdraw from the cell cycle, suggesting that p27 plays a role in the early events regulating withdrawal of cells from the cell cycle. We have further shown that in the absence of this timely withdrawal, estradiol regulation is perturbed, explaining in part how fertility is compromised at the level of implantation. These data support the interpretation of our previous observations on oligodendrocyte differentiation about a role for p27 in establishing the nonproliferative state, which in some cases (oligodendrocytes) is required for differentiation, whereas in other cases it is required for the proper functioning of a differentiated cell (luteal cell).

Animals↗

PubMed1997

9-Aminocamptothecin by 72-hour continuous intravenous infusion is inactive in the treatment of patients with 5-fluorouracil-refractory colorectal carcinoma.

BACKGROUND: 9-Aminocamptothecin (9AC) and its parent compound, camptothecin, have shown outstanding preclinical activity against colorectal carcinoma. Irinotecan (CPT-11), another camptothecin derivative, has demonstrated clinical activity in patients with 5-fluorouracil (5-FU)-refractory colorectal carcinoma. METHODS: The authors performed a Phase II trial of 9AC involving patients with measurable metastatic colorectal carcinoma who had progressed through only one prior regimen of 5-FU-based chemotherapy. 9AC was given initially at a dose of 59 microg/m2/hour by continuous intravenous infusion for 72 hours, with treatments repeated every 14 days. Granulocyte-colony stimulating factor was given on Days 5-12. RESULTS: Sixteen patients were treated on this trial. Fourteen were evaluable for response. Contrary to expectations, no major objective antitumor responses were observed. Eight patients experienced stable disease for a median of 4.1 months (range, 2.2-9.5 months). Toxicities, especially myelosuppression, were severe and necessitated a 15% reduction in the initial dose after the first 9 patients. Toxicities at this reduced dose remained unacceptable. CONCLUSIONS: 9AC did not demonstrate substantial activity against 5-FU-refractory colorectal carcinoma on the schedule studied. Toxicities at the doses and schedule studied were unacceptable in this patient population. Based on their results, the authors consider it unlikely that 9AC administered as a 72-hour continuous intravenous infusion will play a major role in the treatment of colorectal carcinoma.

Adult↗

PubMed1997

On-column monitoring of secretion of catecholamines from single bovine adrenal chromaffin cells by capillary electrophoresis.

The secretion of catecholamines from individual bovine adrenal medullary cells was quantitatively monitored by capillary electrophoresis with laser-induced native fluorescence detection. By using a physiological balanced-salt solution as the running buffer for CE, the amount of norepinephrine (NE) and epinephrine (E) secreted by their physiological secretagogue, acetylcholine, and the amount remaining in a single cell can be simultaneously quantified. Among the six different glands (from separate cows) studied, a predominance of E-rich cells were found. There was no apparent relationship between the ratio of NE/E released and the original NE/E content in the cell. The secretion process was also monitored dynamically with this method by continuously passing acetylcholine over the cell during stimulation. From the peak width and shape of the released material, one can estimate the time scale of the release process.

Animals↗

PubMed1997

Nucleotide-induced stable complex formation by HIV-1 reverse transcriptase.

Nondenaturing gel electrophoresis was used to study the nucleotide substrate-induced conformational change in reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1). Dead-end complex was formed between HIV-1 RT, dideoxynucleotide chain-terminated primer, and DNA template in the presence of deoxynucleotide triphosphate (dNTP) complementary to the next position on the template. Complexes which form in the absence of the next complementary dNTP were disrupted by adding excess poly(rA)/oligo(dT) or heparin just prior to electrophoresis. Dead-end complex formation by noncomplementary dNTP's or ribonucleotides was at least 2000-fold less efficient than with the complementary nucleotide. When dA was the next nucleotide on the template, analogues of dTTP supported dead-end complex formation with increased apparent Kd (dTTP < dideoxy-TTP approximately alpha-thio-dTTP < dUTP < 3'-azidothymidine triphosphate). A similar relationship was observed for dGTP analogues across from dC on the template (dGTP < dideoxy-GTP < alpha-thio-dGTP << dITP < dideoxy-ITP). The optimal length of the primer/template duplex region for dead-end complex formation was between 20 and 32 base pairs. Primer-template with a mismatched primer terminus did not support dead-end complex formation, and primer terminated with 3'-azidothymidine formed dead-end complex with 25-fold elevated apparent Kd. By contrast, dead-end complex formation on primer terminated with dideoxy-IMP base paired with dC on the template was more efficient than on primer terminated with dideoxy-GMP. Implications for the mechanisms of discrimination between nucleotide analogues by HIV-1 RT are discussed.

DNA Primers↗

PubMed1997

Design, synthesis, and biological activities of four angiotensin II receptor ligands with gamma-turn mimetics replacing amino acid residues 3-5.

Disulfide cyclization is a powerful method for reducing the conformational space of a peptide. This in turn may enable the study of its bioactive conformation. Several analogues of angiotensin II (Ang II) containing a disulfide bridge between amino acids 3 and 5 have been reported. Among these the cyclic octapeptides c[Hcy3,5]-Ang II, c[Cys3,5]-Ang II, and c[Pen 3,5]-Ang II showed significant activity at Ang II receptors. We have performed conformational analysis studies using theoretical calculations and 1H-NMR spectroscopy on tripeptide model compounds of these cyclic octapeptides which show that the cyclic moieties of c[Cys3,5]-Ang II and c[Pen3,5]-Ang II preferentially assume an inverse gamma-turn conformation. On the basis of these results, we substituted amino acid residues 3-5 in Ang II with two different gamma-turn mimetics giving four diastereomeric Ang II analogues. Interestingly, two of these are equipotent to Ang II in binding to AT1 receptors. In the contractile test using rabbit aorta rings, one of the analogues is an agonist with full contractile activity approximately equipotent to c[Pen3,5]-Ang II but 300-fold less potent than Ang II. This low potency may suggest that Ang II does not adopt a gamma-turn in the 3-5 region when interacting with the receptor.

Angiotensin II↗

PubMed1997

Monitoring single-cell pharmacokinetics by capillary electrophoresis and laser-induced native fluorescence.

The quantification of insulin released from single cells of the insulin-secreting cell line beta TC3 permeabilized by digitonin is demonstrated. A simple method for monitoring the on-column release process by using capillary electrophoresis and laser-induced native fluorescence detection is described. Quantitative measurements of both the amount of insulin released and the amount remaining in the cell can be achieved simultaneously. This protocol provides an alternative approach to the study of cell secretion in the fields of neuroscience and endocrinology.

Cell Line↗