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Biomedical subjects

I Vermes

Publications and source records attributed to I Vermes.

At least 55 records · Page 3Linked to original sources
PubMed1998

Ex vivo evidence of lymphocyte apoptosis in hairy cell leukemia, induced by 2-chlorodeoxyadenosine treatment.

In all living cells phosphatidylserine (PS) is located at the cytosol side of the membrane and becomes exposed at the cell surface only during necrosis or apoptosis. This phenomenon allows measurement of cell death on a cell-by-cell basis, using labeled Annexin V, which has a strong affinity to PS. Two patients with hairy cell leukemia (HCL) who had relapsed after splenectomy and alpha-interferon therapy were treated with 2-chlorodeoxyadenosine (2-CdA) for 7 days. Blood samples were taken from the start of therapy until day 22. Percentages of HCL cells, T cells, B cells, and NK cells were measured with PE-labeled monoclonal antibodies by flow cytometry (FCM). The absolute lymphocyte count dropped rapidly to almost zero in both patients within 7 days. The disappearance rate of lymphocyte subfractions did not show a specific pattern. The percentage of apoptosis in lymphocyte subfractions was measured in freshly prepared cell samples by FCM with FITC-labeled Annexin V in the propidium iodide-negative (non-necrotic) cell fraction. Percentages of PS-positive cells increased gradually till a nadir of Annexin V positivity was reached at 14 and 16 days. Because during the first week the absolute cell counts became almost zero, the absolute numbers of PS-positive cells were still extremely low, i.e., less than 0.1x10(9)/l. Nevertheless, we observed apoptotic cells in circulation after 2-CdA therapy. To our knowledge, this is the first report of the occurrence of apoptosis ex vivo in circulating blood cells after cytotoxic therapy.

Annexin A5↗
PubMed1998

Apoptosis- and necrosis-inducing potential of cladribine, cytarabine, cisplatin, and 5-fluorouracil in vitro: a quantitative pharmacodynamic model.

PURPOSE: The purpose of this study was to characterize the concentration-dependent induction of apoptosis by anticancer drugs in vitro. METHODS: The apoptosis- and necrosis-inducing potential of the anticancer drugs cladribine (CDA), cytarabine (ARA-C), cisplatin (CDDP), and 5-fluorouracil (5FU) were studied in vitro in the human leukemia cell lines HSB2 and Jurkat using a flow-cytometry assay that permits the simultaneous quantification of vital, apoptotic, and necrotic cells by double-staining with fluorescein isothiocyanate (FITC)-labeled Annexin-V and propidium iodide. The results were fit to different multicompartmental models and the sensitivity of the cell lines to apoptosis and necrosis was estimated. RESULTS: A time- and dose-dependent decrease in vital cells as well as an increase in apoptotic and necrotic cells was observed in HSB2 cells upon continuous incubation with 10(-5)-10(-7) MCDA, 10(-5)-10(-8) MARA-C, 5 x10(-5)-5 x 10(-6) M CDDP, and 10(-4)-10(-5) M 5FU, whereas no effect was observed relative to controls upon incubation with 10(-8)-10(-9) M CDA, 10(-9) M ARA-C, 10(-7)-10(-8) M CDDP, or 10(-6)-10(-9) M 5FU. In Jurkat cells, apoptosis- and necrosis-inducing effects were observed at 10(-4)-5 x 10(-6) M CDA, 10(-5)-10(-7) M ARA-C, 5 x 10(-5)-5 x 10(-6) M CDDP, and 10(-4)-10(-5) M 5FU. In all experiments, apoptotic cells reached a peak after 6-48 h of drug exposure. These data were best fit by a model in which vital cells became irreversibly apoptotic by a direct pathway and necrotic by an irreversible indirect pathway following the apoptotic state (mean R = 0.9876; range 0.9510-0.9993; mean modified Akaike's information criterion 3.88; range 1.86-5.82) and the rate constants of either pathway (Kva and Kan, respectively) were assessed. The sensitivity of both cell lines to apoptosis and necrosis (expressed as EC50 and Emax values) induced by the anticancer drugs could be calculated from the sigmoidal concentration-effect curves. Furthermore, it was shown that drug treatment (10(-6) M CDA or 10(-6) M ARA-C) potentiated the apoptosis-inducing effects of irradiation (6 Gy) but not its necrosis-inducing potential. CONCLUSION: This study demonstrates that CDA, ARA-C, CDDP, and 5FU possess concentration-dependent apoptosis-inducing potential in the cell lines studied. The cytotoxic mechanism and cell-killing potential of these drugs is different, which is reflected by different EC50 and Emax values. Furthermore, a method for pharmacodynamic modeling is introduced that permits a quantitative approach for the assessment of the sensitivity of tumor cells to anticancer drugs and combined treatments.

Antineoplastic Agents↗
PubMed1998

Follicle-stimulating hormone measured in unextracted urine: a reliable tool for easy assessment of ovarian capacity.

OBJECTIVE: To determine the presence of FSH in unextracted urine of perimenopausal women using a microparticle enzyme immunoassay kit on an AxSYM random access immunoassay analyzer. DESIGN: Controlled descriptive study. SETTING: A large teaching hospital and infertility clinic. PATIENT(S): Forty perimenopausal women aged 32-55 years admitted to our clinic for a gynecological operation. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Mean serum FSH level and urinary FSH in early-morning urine, in a random void urine sample, and in 24-hour urine on the same day. FSH in urine on the day of excretion and 1 and 4 weeks thereafter, stored under various conditions. FSH in urine before and after extraction. RESULT(S): The Pearson's correlation coefficient between mean serum FSH levels and urinary FSH in early morning urine was 0.904, in a random void 0.915, and in 24-hour urine 0.857. Determination of optimal storage conditions revealed that urine was best kept at 4 degrees C without any additive. The correlation between FSH in extracted and unextracted urine was 98.9%. CONCLUSION(S): In perimenopausal women, FSH can be reliably measured in unextracted urine. The correlation between urinary FSH and a random void urine sample and mean FSH from a serial serum sample is very high. Urine can be stored for 4 weeks at 4 degrees C without loss of FSH immunoreactivity.

Adult↗
PubMed1998

Apoptotic cell death in human granulosa-lutein cells: a possible indicator of in vitro fertilization outcome.

OBJECTIVE: To determine whether women who do not conceive during an IVF treatment despite normal FSH levels have a higher rate of apoptosis in their granulosa-lutein cells than women who do conceive. DESIGN: Prospective. SETTING: Large teaching hospital and fertility center. PATIENT(S): Patients with normal FSH levels undergoing an IVF treatment. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Outcome of the IVF treatment and percentage of apoptotic granulosa-lutein cells. RESULT(S): A significantly lower percentage of granulosa-lutein cells were apoptotic in patients who became pregnant compared with those who did not become pregnant. A higher basal FSH level was significantly correlated with the duration of the stimulation, and the number of follicles was significantly inversely correlated with the number of ampules of FSH used and the duration of the treatment. The number of embryos was significantly correlated with the number of oocytes, and significantly inversely correlated with the number of apoptotic granulosa-lutein cells. CONCLUSION(S): Fewer granulosa-lutein cells are apoptotic in women who have an ongoing pregnancy after IVF treatment than in women who do not conceive.

Adult↗
PubMed1998

Early features of apoptosis detected by four different flow cytometry assays.

The objective of this study was to investigate the sensitivity, specificity and reproducibility of some frequently used apoptosis assays. The degree of apoptosis was tested in two T-lymphoblastoid cell lines, HSB and Jurkat, in which apoptosis was induced by ionizing radiation. HSB and Jurkat samples were taken before, and 0, 2, 4, 6, 8 and 24 h after irradiation with 6 and 10 Gray, or with 10 and 14 Gray, respectively. Four frequently used flow cytometric techniques were evaluated: (i) Annexin V/Propidium Iodide assay, detecting the translocation of phosphatidylserine to the outer leaflet of the plasma membrane, simultaneously with preservation of the membrane integrity; (ii) Terminal deoxynucleotidyl Transferase (TdT) Uridine triphosphate (UTP) nick end labelling (TUNEL), revealing the presence of DNA strand breaks; (iii) DNA-flow cytometry, measuring DNA-stainability (DNA-fragmentation assay) and (iv) Phycoerythrin-labelled (PE) Apo2.7-assay, a monoclonal antibody against 7A6 antigen, a protein, which becomes exposed upon the mitochondrial membrane during apoptosis. As a general standard for identifying that apoptosis had occurred, the cells were assessed for the presence of DNA-laddering on agar gel electrophoresis and by demonstration of characteristic cell morphology. Results were as follows: Fluorescein Isothiocyanate (FITC)-labelled Annexin V/Propidium iodide flow cytometry appeared to be the most sensitive, the most specific and the most user-friendly test for measurement of apoptosis of cells in culture conditions in suspension. The expression of 7A6 antigen on the mitochondrial membrane appeared to be not specific for apoptotic cell death.

Journal Article↗
PubMed1998

Insulin-like growth factor (IGF)-I and IGF binding protein-3 concentrations in fluid from human stimulated follicles.

Insulin-like growth factor-I (IGF-I) and IGF binding protein-3 (IGFBP-3) play an important role in regulating follicle growth and maturation. We have evaluated whether responsiveness to gonadotrophins during an in-vitro fertilization (IVF) treatment is related to follicular fluid IGF-I and IGFBP-3 concentrations. We also investigated if a difference is present in IGF-I and IGFBP-3 concentrations between patients treated with human menopausal gonadotrophin (HMG) and patients treated with highly purified follicle stimulating hormone (FSH). We have measured IGF-I and IGFBP-3 in follicular fluid from pre-ovulatory follicles in an IVF programme. All 70 patients were stimulated after being down-regulated with a gonadotrophin-releasing hormone (GnRH) analogue. IGF-I concentrations in follicular fluid were significantly inversely correlated with the number of ampoules FSH administered and number of days of FSH administration, and significantly correlated with the number of follicles aspirated. IGFBP-3 concentrations were not correlated with any other parameter measured nor were IGF-I and IGFBP-3 concentrations correlated. IGFBP-3 concentrations were significantly higher in patients receiving highly purified FSH compared with patients receiving HMG (P < 0.005). These results are new evidence that IGF-I concentration in follicular fluid is higher in women who respond better to follicular stimulation, i.e. women who grow many follicles, women who need a shorter duration of stimulation and women who need fewer ampoules FSH before oocyte retrieval.

Adult↗
PubMed1997

Apolipoprotein E genotyping in patients with neurodegenerative diseases.

OBJECTIVES: There is a growing demand to perform apolipoprotein E (Apo-E) genotyping on neuropathologic archive material. Due to the extremely long fixation time, this material is unsuitable for routinely used Apo-E genotyping methods. We present an investigation into the applicability of a new method. DESIGN AND METHODS: An Apo-E genotyping method was tested for use on formalin-fixed paraffin-embedded brain tissue, using semi-nested PCR followed by hybridization with biotin-labeled allele-specific oligonucleotides, and chemiluminescent detection. The method was applied to 88 archive samples of different neurologic disorders. RESULTS: With this technique 76% (67/88) of the samples could be genotyped. The crucial step is the semi-nested PCR. All the samples from which a PCR product could be obtained, the Apo-E gene could be genotyped without interpretation problems. Seventy-six percent of the samples that could not be genotyped, were fixed in unbuffered formalin. CONCLUSIONS: This technique offers a good Apo-E genotyping method applicable on neuropathological archive material in order to support in retrospect clinical studies.

Alzheimer Disease↗
PubMed1997

Apoptosis: molecular mechanisms and implications for cancer chemotherapy.

Apoptosis, or programmed cell death, is an orderly and genetically controlled form of cell death. In a morphological sense, it differs from necrosis in that cellular shrinkage and chromatin condensation occurs, followed by fragmentation of nuclear components within membrane-bound vesicles which are cleared by phagocytosis without damage to adjacent tissue. The molecular pathway includes an initiating phase, which starts after signalling by external triggers, such as ligation to distinct receptors or by endogenous mechanisms related to aging or to exogenous irreversible cellular or nuclear damage. The initiation phase is followed by a decision phase. During this phase transduction occurs of the apoptotic signal to nuclear and cytoplasmatic target enzymes, which includes activation of endonucleases and enzymatic alterations of the cytoskeleton. There are numerous proteins and lipid-derived moieties which modulate the apoptotic mechanism in positive or negative direction. The execution phase is started when the cell has arrived at a stage of no return. The nuclear DNA is cleaved into multiples of 180-200 basepairs, the plasma membrane integrity and the mitochondria remain initially intact, the cell splits up into apoptotic bodies, small vesicles which enclose the nuclear and cellular remnants. Finally, the clearing phase is arrived, when the apoptotic bodies are phagocytosed by adjacent cells and macrophages. It is thought that the pharmacodynamics of anticancer drugs consists of two distinct steps. The first step includes the interaction with its cellular target; which is not lethal per se. The commitment of the cell to undergo apoptosis forms the second step. The efficacy of anticancer drugs is determined by the ability to selectively sensitize tumor cells to apoptosis, which depends to a large extent from the expression of various oncogenes, such as bcl-2, p53, bax, ras, c-myc and others, and from endogenous factors. It is a challenge in pharmacological research to explore apoptosis by modulating the extrinsic and intrinsic regulators in a positive or negative direction in order to improve the efficacy of anticancer treatment.

Antineoplastic Agents↗
PubMed1997

Urinary albumin excretion rate during angiotensin II infusion in microalbuminuric patients with insulin and non-insulin-dependent diabetes mellitus.

As angiotensin-converting enzyme inhibition is accompanied by a marked decrease in glomerular protein loss, the hypothesis was tested that an increase of the glomerular transcapillary hydraulic pressure difference by exogenous angiotensin II would increase microalbuminuria in patients with insulin (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM). Acute effects of increasing doses of angiotensin II (1, 3 and 6 ng/kg/min) were studied on mean arterial pressure (MAP), glomerular filtration rate (GFR), effective renal plasma flow (ERPF), filtration fraction (FF), total renal vascular resistance (TRVR), and urinary albumin excretion rate (UAER) in 11 IDDM and 11 NIDDM microalbuminuric patients. Angiotensin II infusion changed MAP from 100 +/- 3 mmHg at baseline to 105 +/- 3, 111 +/- 3, and 116 +/- 3 mmHg (P < 0.001), ERPF from 542 +/- 29 to 478 +/- 24, 429 +/- 23, and 382 +/- 19 ml/min (P < 0.001), FF from 20.2 +/- 0.06 to 23.1 +/- 0.7, 27.1 +/- 1.1, and 29.8 +/- 1.2% (P < 0.001), and TRVR from 9454 +/- 809 to 11,158 +/- 930, 13,310 +/- 1206, and 15,538 +/- 1362 dyne s cm-5 (P < 0.001). GFR and UAER, however, did not change significantly. Therefore, during angiotensin II infusion ERPF decreased, while FF and TRVR increased. As UAER and GFR remained unchanged, the presumed rise in intraglomerular capillary pressure by exogenous angiotensin II did not increase UAER. We suggest that during manipulation of the renin-angiotensin system, as in other renal diseases with proteinuria, factors other than glomerular transcapillary hydraulic pressure determine the degree of urinary albumin loss in microalbuminuric IDDM and NIDDM patients.

Adult↗
PubMed1997

Apoptosis and secondary necrosis of lymphocytes in culture.

It has been reported that cultured peripheral B lymphocytes of chronic lymphocytic leukemia (B-CLL) patients show a high degree of apoptosis (programmed cell death). Till now, no data exist about the occurrence of in vitro apoptosis of normal B and T cells. We measured the amount of apoptosis and secondary necrosis (type 2 necrosis) in B-CLL lymphocytes and in normal peripheral B and T lymphocytes in culture. Observations were made on B-CLL lymphocytes and on normal B and T cells purified by immunomagnetic cell sorting. Apoptosis and secondary necrosis were measured using a recently described sensitive flow-cytometric assay, probing simultaneously for cell surface exposure of phosphatidylserine with the use of FITC-labeled annexin-V and for cell membrane integrity as demonstrated by the exclusion of propidium iodide. The degree of in vitro apoptosis and secondary necrosis of normal B cells appears to be higher than that of normal T cells, and even higher than that of B-CLL cells. The results indicate that cultured mature circulating normal B lymphocytes exhibit a higher cell death rate than normal T cells and B-CLL lymphocytes.

Annexin A5↗
PubMed1996

Hypo-osmotic swelling test: a reliable screening assay for routine semen specimen quality screening.

We investigated whether the hypo-osmotic swelling (HOS) test is a reliable screening method for routine semen specimen quality screening. Of 159 male patients, 171 semen samples were investigated using the HOS test as well as routine semen specimen screening used in our clinic. There was a significant correlation between the HOS test and most semen parameters. There was no significant correlation between the HOS test and the percentage of morphologically normal spermatozoa in the initial semen sample. The HOS test is a reliable screening method for routine semen quality screening.

Humans↗
PubMed1996

Apoptosis: programmed cell death in fetal development.

Controlled death of cells is as much a part of embryonal development as is cell proliferation and differentiation. This cell suicide is controlled by cell genes involved in induction or prevention of programmed cell death (PCD). During embryogenesis PCD implicates cell elimination, necessary in fashioning of the body, moulding of tissues. PCD is often used synonymous with the designation apoptosis, which indicates an endogenous cell suicide program by which useless or crippled cells are eliminated. Apoptosis occurs in normal tissue turnover, in organ involution after withdrawal of trophic hormones, in distinct cells after deprivation of growth factors or specific stimuli and in cells which have undergone sublethal damage. During PCD the nucleus breaks up into DNA fragments of 180-200 kD and the endoplasmic reticulum transforms into vesicles, which are released as apoptotic bodies into the extracellular space. The apoptotic bodies, containing cell organelles and nuclear fragments, are phagocytosed by neighboring cells. Electron micrographs of embryos have revealed the presence of numerous cells with the characteristic features of apoptosis. Experiments, in which small tissue fragments were explanted to other regions, have proven that focal apoptosis is under control of genetic, hormonal and local tissue factors. Morphological analysis has shown that most of the ovarian follicles undergo during development apoptosis, resulting in follicle atresia. Only a small proportion escapes PCD. Growth factors and estrogens have been identified as follicle survival factors, androgens and gonadotropin releasing hormones are potentiating apoptosis of the follicle. An exaggerated PCD or a defective apoptosis during embryogenesis may cause developmental abnormalities. Certain viruses can inhibit apoptosis, while metabolic stress or damage of cell structures can induce apoptosis. Therefore not only viral infections, also drugs and chemical or physical injuries during embryogenesis may interfere with the balanced PCD and thus induce malformations. Drugs and therapy designs directed to modulate the apoptotic process will offer new approaches to the prevention of congenital malformations.

Animals↗