Breast cancer characteristics are modified by first trimester human placenta: in vitro co-culture study.

BACKGROUND: Pregnant women with breast cancer present with a more advanced disease compared with non-pregnant women. Nevertheless, breast cancer metastasis to the placenta is rare. Trophoblast/tumor implantations share the same biochemical mediators, while only the first is stringently controlled. We hypothesized that the same mechanisms that affect/restrain placental implantation may inhibit metastatic growth in the placenta. We aimed to analyze the effects of human placenta on breast cancer cells. METHODS: First trimester human placental explants were co-cultured with MCF-7/T47D-eGFP tagged cells. Following culture, placenta/cancer cells/both were fixed, paraffin embedded and sliced for immunohistochemical analysis or sorted by their eGFP expression for future analysis. The tested parameters were: proliferation (immunohistochemistry)/cell cycle (FACS), apoptosis (immunohistochemistry/FACS), cell count/adhesion/distribution around the placenta (cell sorter, visual observation and counting), matrix metalloproteinase activity (zymogram) and estrogen receptor (ER) expression (western blotting, immunohistochemistry). RESULTS: Reduced breast cancer cell numbers (45%↓, 48%↓ for MCF-7/T47D, respectively, P < 0.05) were observed near the placenta. The placenta elevated MCF-7 sub-G1 phase and modestly elevated apoptosis (3-17%↑ for T47D/MCF-7, respectively, P < 0.05). Our findings demonstrate breast cancer cell migration from the placenta as: (i) T47D/MCF-7 cells changed their morphology to that of motile cells; (ii) elevated MMPs activity was found in the co-culture; (iii) placental soluble factors detached breast cancer cells; and (4) the placenta reduced MCF-7/T47D cells' ER expression (a characteristic of motile cells). CONCLUSIONS: MCF-7/T47D cells are eliminated from the placental surroundings. Analyzing the causes of these phenomena may suggest biological pathways for this event and raise new therapeutic targets.

Tetraspanin-induced death of myeloma cell lines is autophagic and involves increased UPR signalling.

BACKGROUND: Multiple myeloma (MM) therapy is hindered by the interaction of the heterogeneous malignant plasma cells with their microenvironment and evolving drug resistance. We have previously shown that the membranal tetraspanins, CD81 and CD82, are under-expressed in MM cells and that their reintroduction causes massive non-apoptotic death. In this study, we aimed to characterise the tetraspanin-induced MM death. METHODS: Multiple myeloma cell lines were transiently transfected with eGFP-CD81N1/CD82N1 fusion proteins and assessed for death mode by flow cytometry (propidium iodide, ZVAD-fmk, 3MA), activation of unfolded protein response (UPR), and autophagy (immunoblot, RT-PCR). RESULTS: Cell death induced by CD81N1 and CD82N1 in MM cell lines was autophagic and involved endoplasmic reticulum (ER)-stress manifested by activation of UPR pathways, PERK (protein kinase-like ER kinase) and IRE1 (inositol-requiring 1). We also established the relative X-box binding protein 1 baseline expression levels in a panel of MM cell lines and their general dependence on autophagy for survival. Timeline of UPR cascades and cell fate supported our results. INTERPRETATION: This is the first publication implicating tetraspanins in UPR signalling pathways, autophagy, and autophagic death. Integration of our findings with published data highlights the unifying dependence of MM cells on ER-Golgi homoeostasis, and underscores the potential of tetraspanin complexes and ER-stress as leverage for MM therapy.

Clinical outcome of low-grade NHL patients with bone marrow involvement.

BACKGROUND: Bone marrow (BM) involvement in low-grade non-Hodgkin's lymphoma (NHL) has a clear impact on patients' survival. The standard practice is morphological examination of BM biopsy at diagnosis. The clinical significance of flow cytometry (FC) analysis of BM aspirates is largely unknown. MATERIALS AND METHODS: The medical charts of 70 low-grade NHL patients, who underwent BM biopsy and FC analysis between 1994 and 2004, were reviewed. RESULTS: Forty-three patients (61.4%) were BM+ by morphology, while in those without morphological involvement by lymphoma FC was positive in 9 (BM-FC+, 12.9%) and negative in 18 (BM-FC-, 25.7%). The median treatment-free period was shorter in the BM+ and BM-FC+ groups compared with the BM-FC- group (1 and 4 months vs. 31 months, respectively) (log-rank test, P = 0.0195). The median survival time was not reached for the BM-FC- patients, whereas for BM+ and BM-FC+ patients it was 129 and 89 months, respectively, with no significant difference between them [the difference between the BM-FC- and the two other groups was statistically significant (log-rank test, P = 0.029)]. CONCLUSIONS: The outcome of low grade NHL in patients who had BM involvement by FC alone or by morphology was similar. If confirmed, these findings suggest a modification in the workup and management of localized low grade NHL.

Fluorouracil induces apoptosis and surface molecule modulation of peripheral blood leukocytes.

Little is known about the direct effect of chemotherapy on normal peripheral blood leukocytes (PBL) or its contribution to leukopenia. We examined 5'-fluorouracil's (5FU) effect on PBL apoptosis and adhesion molecules' expression in a single-drug solid-tumor model. Possible apoptosis mediators were examined. The study included 32 colorectal cancer patients; apoptosis was determined by annexin-V binding and light-scatter morphology before and after drug infusion. CD18, CD11a, CD11b, and CD63 membranal levels were assayed by flow cytometry. Apoptosis was increased post-5FU administration in neutrophils (PMN), monocytes and lymphocytes (P < 0.05). Levels of Fas receptor and activated caspase 3 did not vary indicating that the process was not mediated by caspase 3 in the timeframe studied. Reduced CD63 on monocytes and decreased CD18 expression on PMN and non-apoptotic monocytes were observed (P < or = 0.05). CD11a,b expression did not vary. Decreased CD18 and CD63 levels were demonstrated in apoptotic and non-apoptotic PBL implying a more direct association with the drug itself.

Expression of tetraspanins in peripheral blood leukocytes: a comparison between normal and infectious conditions.

The role of tetraspanins is undefined, despite their detection in diverse cell types and functions. This study addresses the characterization of tetraspanin expression levels in normal peripheral blood leukocytes (PBL) and in patients with bacterial infection. Membranal and cytoplasmic expression of CD9, CD53, CD63, CD81, CD82 and CD151 in polymorphonuclears (PMN), monocytes, B and T lymphocytes was assessed using flow cytometry. Results suggested that for normal PBL, PMN are distinguished by dominant cytoplasmic CD63; monocytes and B cells prevailingly express CD53; CD82 is primarily expressed on T-cell membranes. However, a major trend of downregulation was demonstrated for the examined tetraspanins, except CD63, in all patients' PBL subtypes. Therefore, tetraspanin modulation in infections may be attributed to elevated leukocyte motility in immune reactions and this is compatible with the previous publications of tetraspanins as metastasis suppressors. This work represents the first comprehensive baseline of tetraspanin expression in normal PBL and in infectious disorders.

Induction of apoptosis by ultrasound application in human malignant lymphoid cells: role of mitochondria-caspase pathway activation.

In the present study, we have focused on the specific question of whether ultrasound application (ULS) delivered with optimized parameters for cavitation generation can stimulate apoptosis in lymphoid cell lines. Suspended T and B lymphoid cell lines (Jurkat and Raji, respectively) were exposed to low frequency ULS (750 KHz) at an intensity level of 54.6 W/cm(2) spatial peak temporal average (SPTA) at focal area, which was found to be the optimal physical parameter to induce apoptosis in these malignant cell lines. Unsonicated cells and cells exposed to gamma-radiation (20 Gy) using (137)Cs source were used as control. Apoptosis was evaluated by cell morphology changes, cell-cycle analysis, and phosphatidylserine exposure. Fraction of cells with low mitochondria membrane potential was observed 1 h after sonication, accompanied by cytochrome c release from mitochondria to the cytosol and caspase-3 activation. Here we present evidence that ULS exposure with cavitation formation on malignant lymphoid cell lines differs from gamma-radiation and is associated with time-dependent apoptosis, which is mitochondria-caspase dependent.

Diffuse muscular haemorrhage as presenting sign of juvenile systemic lupus erythematosus and lupus anticoagulant hypoprothrombinaemia syndrome.

Lupus anticoagulants are closely related to systemic lupus erythemathosus (SLE) and to thrombotic events. We describe a 12 year-old girl with a bilateral intramuscular haemorrhage of the gastrocnemius muscles as her main initial presentation of juvenile SLE. Laboratory work-up revealed lupus anticoagulant-hypoprothrombinaemia syndrome (LAHS) with very low levels of factor II due to autoantibodies. She showed a good initial clinical and laboratory response to prednisone therapy, however steroid dependency developed. To the best of our knowledge, this is the first case reported of juvenile SLE presenting with LAHS.

Tamoxifen modulates apoptotic pathways in primary endometrial cell cultures.

Clinical data indicate that tamoxifen (TAM) therapy may cause an increased risk of endometrial pathology in postmenopausal but not in premenopausal women. Molecular mechanisms of the uterotrophic activity of TAM have not been clearly established nor its relevance to apoptosis in endometrial cells. The present study was implemented to evaluate the apoptotic effect of TAM on primary endometrial cell cultures in the presence or absence of steroid hormones (SHs). A total of 14 primary endometrial cell cultures were established and maintained both with and without SHs. Cell cultures were treated for 24 h with either 20 microM TAM or 10 nM estradiol. Apoptotic cells presented in a pre-G1 peak and the expression of bcl-2 were studied using flow cytometry. All endometrial cell cultures maintained in a SH-containing environment, except one, responded to TAM by a significant increase (P = 0.03) in the pre-G1 cell fraction, indicating a proapoptotic effect. A significant (P = 0.03) reduction in the pre-G1 peak equivalent to an antiapoptotic response was observed in 6 of 13 cell cultures maintained in a SH-deficient environment. In 4 of 10 cell cultures evaluated in both media, the pre-G1 population was medium dependent. In 8 of 10 cultures evaluated for Bcl2 levels, no trend was found in either media, but a dependency on SH content was observed. Comparison between effects of TAM and estradiol demonstrated identical trends, regardless of the menstrual phase or SH content in cell environments. These results suggest that TAM acts as an estrogen agonist on endometrial tissue in both environments. We conclude that TAM modulates apoptotic pathways in primary endometrial cell cultures. The SH content in the cell environment influences the apoptotic effect of TAM and determines the propensity for a cell to undergo apoptosis or, on the contrary, to resist apoptotic death in response to TAM treatment. This is in concordance with the observed clinical risk of endometrial pathologies in postmenopausal versus premenopausal women.

The prognostic value of DNA ploidy in small renal cell carcinoma.

The objective was to study the prognostic value of Deoxyribonucleic Acid (DNA) ploidy status in small renal cell carcinomas (RCC). The nuclear DNA content of renal cell carcinoma tissues from patients who underwent radical or partial nephrectomy has been analyzed by flow cytometry. The results of the DNA ploidy have been correlated to the size of tumors and disease progression. Of the 50 patients with RCC studied, 8 (16%) progressed. Tumors with non-diploid DNA patterns were found in 24 (48%) of the 50 patients and in 4 of the 8 patients who progressed. Overall the median tumor size in our series was 50 mm. A tumor diameter of 50 mm or less was measured in 26 patients (group I) and above 50 mm in 24 (group II). Non-diploid DNA patterns were found in 11 (42.3%) and 13 (54.2%) patients in groups I and II, respectively. This difference between the groups was not significant. Only one patient in group I (3.8%) developed metastatic disease and died 72 months after the operation. In group II, 7 patients (29.2%) presented tumor progression and 5 died of metastatic disease. The survival probability in group I was 95% at 5 and 8 years (95% CI 70% to 99%) and for group II 94% at 5 years (95% CI 67%-99%) and 67% at 8 years (95% CI 39%-83%). DNA ploidy is an inaccurate predictor of tumor behavior in patients with RCC, even in small tumors. Tumor size is a more significant predictor of outcome.

The effect of storage on the expression of platelet membrane phosphatidylserine and the subsequent impacton the coagulant function of stored platelets.

BACKGROUND: Platelet concentrates (PCs) derived from whole blood and stored under standard blood bank conditions undergo changes that are referred to as the platelet storage lesion. This study assesses the effect of PC preparation and storage on the distribution of phosphatidylserine (PS) in the platelet membrane and the effect that this distribution may have on the thrombogenic potential of stored PCs. STUDY DESIGN AND METHODS: Fresh platelets and PCs donated by healthy donors were obtained. PCs derived from platelet-rich plasma were studied on Day 1, Day 3, and Day 6 of storage under blood bank conditions. RESULTS: Platelet aggregation after exposure to the platelet agonists ADP and epinephrine singly declined progressively, but, when ADP and epinephrine in combination and collagen and thrombin in combination were used as agonists, the decline in platelet aggregation was less marked. PS expression as measured by Annexin V binding (mean and SD) was 2.02 +/- 0.93 percent in fresh platelet samples and increased to 5.39 +/- 4.2 percent on Day 1, 22. 1 +/- 7.1 percent on Day 3, and 39.5 +/- 12.1 percent on Day 6. Platelet prothrombinase activity (mean +/- SD) as measured by thrombin generation increased from 1.49 +/- 0.7 micro per mL in fresh platelet samples to 3.68 +/- 1.1 micro per mL in Day 1 platelets (p<0.001), 5.15 +/- 2.5 micro per mL in Day 3 platelets (p<0.001), and 4.65 +/- 2.48 micro per mL in Day 6 platelets (p<0. 001). CONCLUSION: These results show that PS expression increases after preparation of PCs from platelet-rich plasma and rises progressively during platelet storage under blood bank conditions. Furthermore, the greater PS expression is associated with increased platelet- dependent thrombin-generating capacity.

The diagnostic significance of polyclonal lymphocytosis in pleural effusions.

AIM: To evaluate the diagnostic contribution and clinical relevance of analysing subpopulations of lymphocytes in pleural effusions. METHODS: Forty patients (age >60 years) with newly diagnosed, polyclonal, lymphocyte-rich pleural effusions were evaluated. The following data were collected: demographic characteristics, associated diseases, fluid type, fluid white blood cells count, differential morphology and immunephenotyping, and final diagnosis. RESULTS: Of the 33 patients for whom biochemical data were available, 18 had exudative effusion, while 15 had transudate. Thirty-three fluids contained mostly T cells and only one was B-cell rich. (The lymphocytes of five patients with malignant epithelial cells in the effusion were not subtyped.) Thirty-two of the 33 T-cell rich fluids contained mainly CD4+ lymphocytes. The most common causes of pleural effusion were congestive heart failure (17 patients) and epithelial malignant diseases (eight patients), while none of the patients had tuberculosis. Since most effusions were CD4+ rich, no correlation could be detected between lymphocyte subtyping and diagnosis or the biochemical type of the fluids. Congestive heart failure was significantly associated with transudates, while malignant diseases correlated with exudates. CONCLUSIONS: Most patients with pleural polyclonal lymphocytosis, especially those with transudates, have congestive heart failure. The presence of exudative, lymphocyte-rich effusion is an indication for further evaluation, since it is most commonly associated with malignancy. The clinical value of lymphocyte subtyping is low and this procedure should not be used routinely.

Apoptosis induction of human myeloid leukemic cells by ultrasound exposure.

Therapeutic ultrasound (ULS) and the resulting cavitation process has been shown to induce irreversible cell damage. In this study, we wanted to further investigate the mechanism of ULS-induced cell death and to determine whether apoptosis is involved. High intensity focused pulsed ULS sonication at a frequency of 750 KHz was delivered to HL-60, K562, U937, and M1/2 leukemia cell line cultures. ULS exposure used with induction of transient cavitation in the focal area was delivered with an intensity level of 103.7 W/cm2 and 54.6 W/cm2 spatial-peak temporal-average intensity. As a control, ULS of lower intensity was delivered at 22.4 W/cm2 spatial-peak temporal-average intensity, presumably without generation of cavitation. Our results indicated that DNA damage induced by ULS cavitation did not involve generation of free radicals in the culture media. Morphological alterations observed in cells after exposure to ULS included: cell shrinkage, membrane blebbing, chromatin condensation, nuclear fragmentation, and apoptotic body formation. Apoptotic cells were evaluated by fluorescence microscopy and detected using the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, which identifies DNA breaks, and by the leakage of phosphatidylserine from the inner to the outer side of the membrane layer of treated cells. Some bioeffects induced on sonicated HL-60 cells, such as inhibition of cell proliferation, DNA repair, and cell-dependent apoptosis, were found to be similar to those produced by gamma-irradiation. Thus, much of the cell damage induced by therapeutic ULS in leukemia cells surviving ULS exposure appears to occur through an apoptotic mechanism.

Multiple myeloma: monoallelic deletions of the tumor suppressor genes TP53 and RB1 in long-term follow-up.

Recently, a working-model of a stepwise malignant transformation in the molecular pathogenesis of multiple myeloma (MM) was proposed, involving the tumor suppressor gene TP53 and retinoblastoma gene (RB1) as prominent components of cell cycle control. To further define the role of TP53 and RB1 in disease progression, we retrospectively analyzed by fluorescence in situ hybridization (FISH) cytological material from 16 patients who underwent sequential bone marrow biopsies during the course of their disease. For TP53, no deletions were detected at presentation or during follow-up. It is possible that the patients reported here represent a subset with relatively long survival, and therefore did not demonstrate the TP53 deletions that had been reported in patients with a very poor prognosis. For RB1, monoallelic deletion was demonstrated in nine patients. In each case, the deletion appeared already in the first biopsy analyzed. The presence of a deletion did not affect the rate of tumor progression or the length of follow-up, and thus prognosis. Monoallelic deletions of RB1 appear to be a frequent and early event in the pathogenesis of MM, without obvious relevance for disease progression.

Pleural effusion in patients with non-Hodgkin's lymphoma: a case-controlled study.

BACKGROUND: Pleural effusion is reported in up to 20% of patients with non-Hodgkin's lymphoma (NHL), most often at presentation. However, the prognostic implications of such findings are not clear. The majority of the information in the literature is based on minor observational studies or case reports. Therefore, a case-controlled study was performed to verify the clinical significance of pleural effusion in NHL. METHODS: Seventeen patients with pleural effusion at the time of presentation of NHL were identified. They were categorized by grade of NHL (based on the Working Formulation). Twenty-nine control patients with similar histopathologic characteristics who had Stage III/IV NHL without pleural effusion were matched to these cases by age, time of diagnosis, and treatment. RESULTS: Ten patients with intermediate grade NHL were matched with 23 controls. No statistically significant difference in complete remission or survival rates between these groups was found (P=0.69 and P=0.7, respectively). The remission and survival rates also were similar in the subgroup of patients and controls who were treated with aggressive chemotherapy. Similarly, no difference was found in these parameters between four cases and six matched controls with low grade lymphoma. No matched controls were found for the patients with high grade lymphoma, but these patients had an unfavorable outcome. Fourteen of the 17 studied patients had an exudative type of pleural effusion. Thoracentesis yielded a positive cytologic finding in every case. CONCLUSIONS: The presence of pleural effusion at the time of presentation of NHL does not adversely affect complete remission or survival rates.

Cytokines modulate expression of cell-membrane complement inhibitory proteins in human lung cancer cell lines.

Human lung cancers overexpress several cell-membrane complement inhibitory proteins (CIP). These complement inhibitory proteins are membrane cofactor protein (CD46), decay-accelerating factor (DAF; CD55), and CD59 (protectin). These cell-membrane proteins have a wide normal tissue distribution, are known to protect normal host cells from homologous complement-mediated lysis, and are thought to facilitate tumor escape from immunosurveillance. To study whether proinflammatory cytokines that are involved in cancer growth can modulate cell-membrane CIP expression in lung cancer cells, we studied the effect of interleukin (IL)-1alpha, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma on two human lung cancer cell lines. ChaGo K-1 and NCI-H596 cell lines, undifferentiated carcinoma and lung adenosquamous carcinoma, respectively, were stimulated with different cytokines, and the effects of incubation time and cytokine concentration on cell-membrane CIP expression were studied. Cell-membrane CIP expression was evaluated using flow cytometry and cytokine effect was calculated as percent change in mean fluorescence intensity of each CIP molecule from its untreated control. We found that DAF was the lung cancer cell-membrane CIP molecule that was the most responsive to cytokine stimulation. Maximal stimulatory effect was usually noted 72 h after a cytokine was introduced. In ChaGo K-1 and NCI-H596 lung cancer cell lines, IL-1alpha and TNF-alpha increased DAF expression. IL-1alpha (100 U/ml/72 h) increased DAF expression up to a maximal mean of 45 and 48%, respectively, in comparison with untreated cells. TNF-alpha (1, 000 U/ml/72 h) increased DAF expression up to a mean of 131 and 46%, respectively. IFN-gamma (1 U/ml/72 h) increased DAF expression in NCI-H596 cells up to a mean of 100%, but had a slight inhibitory effect on DAF expression in ChaGo K-1 cells, decreasing expression by a mean of 17% in comparison with untreated cells. We conclude that cell-membrane DAF expression in the studied human lung cancer cell lines is modulated by IL-1alpha, TNF-alpha, and IFN-gamma, and speculate that cytokine-mediated modulation of cell-membrane DAF in human lung cancer cells might affect lung cancer cell biology.

Increased expression of neutrophil and monocyte adhesion molecules LFA-1 and Mac-1 and their ligand ICAM-1 and VLA-4 throughout the acute phase of myocardial infarction: possible implications for leukocyte aggregation and microvascular plugging.

OBJECTIVES: This study sought to evaluate expression of adhesion molecules on neutrophils and monocytes throughout the acute phase of myocardial infarction. BACKGROUND: Neutrophil and monocyte counts increase within days from onset of acute myocardial infarction. Because leukocytes are recruited to the involved myocardial region, we postulated that these activated cells would display an increased expression of adhesion molecules necessary for effective endothelial transmigration. METHODS: We measured the expression of neutrophil and monocyte lymphocyte function associated antigen-1 (LFA-1), Mac-1, very late after activation antigen-4 (VLA-4) and intercellular adhesion molecule-1 (ICAM-1) by flow cytometry throughout the acute phase of acute myocardial infarction in 25 patients and 10 age-matched control subjects. RESULTS: Expression of Mac-1 on neutrophils increased significantly, whereas no expression of VLA-4 and ICAM-1 was detected. The expression of LFA-1, Mac-1, VLA-4 and ICAM-1 on the monocyte cell membrane in patients with an acute myocardial infarction was increased compared with that in control subjects by 22% (on day 7), 67%, 13% and 44% (all on day 4), respectively (all p < 0.001). Elevated density of monocyte-specific CD14 in the AMI versus the control group was also shown (30%, p < 0.001). CONCLUSIONS: Increased expression of neutrophil and monocyte adhesion molecules may contribute to their adhesion to endothelium in the ischemic territory. This adhesion could feasibly precipitate vasoconstriction or add a local thrombotic effect due to tissue factor expression secondary to Mac-1 engagement. In addition, the manifestation of increased density of LFA-1 and Mac-1 by activated leukocytes with monocytes also expressing ICAM-1 suggests that leukocytes may form microaggregates that could cause microvascular plugging. This mechanism may facilitate the occurrence of the "no-reflow" phenomenon or slow coronary filling after acute myocardial infarction.

Lymphoma with multi gene rearrangement on the level of immunoglobulin heavy chain, light chains, and T-cell receptor beta chain.

A unique case with diffuse mixed malignant lymphoma was investigated for gene rearrangement on the level of T-cell receptor (TCR), heavy chain immunoglobulin (Ig), and both light chains. Cell phenotype was examined with immunofluorescence techniques using antibodies against surface immunoglobulins (SIg) and the kappa and lambda light chains. Monoclonal antibodies were used against CD3, CD4, CD5, CD8, CD10, CD19, CD22, HLA-DR, and TdT. Gene rearrangement analysis for monoclonality determination was carried out with restricted DNA (EcoR I and Hind III) hybridized with one of the following 32P-labelled probes: T-cell receptor (TCR beta), immunoglobulin heavy chain (JH), k light chain, and lambda light chain. Phenotyping of the cell population from the excised lymph node (LN) revealed the presence of 66% B-cells and 35% T-cells. Most of the B cells (94%) expressed mu heavy chain only. Expression of both light chains was negligible (k = 7% and lambda = 2%). Gene rearrangement, which indicates monoclonality, was positive on the level of TCR, Ig heavy chain, and both light chains. The data obtained suggests a neoplastic transforming event in lymphoid stem cells, which preceded the subsequent differentiation process into either B or T lymphoma.

Cellular and humoral immune response to exercise among gymnasts and untrained girls.

Recent studies reported reduced immunity in athletes following exercise. Physical activity affects both cellular and humoral immune functions. Scant information exists on exercise-induced changes in the immune system among children. The purpose of the present study was to investigate the effect of aerobic exercise on several aspects of cellular and humoral functions among 10-12 year-old highly trained female gymnasts (n = 7) and untrained girls (n = 6). All girls were pre-pubertal. Venous blood samples were drawn before, immediately after and 24 h following 20 min of treadmill running (heart rate 170-180 beats.min-1). White blood cells' number rose significantly following exercise and remained elevated for 24 h. The increase in leukocyte number was due to an increase in granulocytes as well as an increase in lymphocytes and monocytes. While neutrophil count returned to basal values after 24 h, lymphocytes and monocytes number remained elevated 24 h following exercise. Exercise resulted in a significant elevation of T cell lymphocytes, T helpers, T suppressors and natural killer cells. All values returned to normal after 24 h. There were no changes in B cell lymphocytes following exercise. Exercise had no effect on serum IgA, IgM, IgE, IgG and sub-types of IgG (IgG1, IgG2, IgG3 and IgG4). No differences were observed between gymnasts and untrained girls. In summary, the exercise-induced changes in cellular and humoral immune functions among the girls were generally similar to those described in adults. Whether the transitory effects of exercise on the immune system are related to increased susceptibility to illness is still questionable.

Flow cytometric analysis of the platelet surface area and surface density of glycoprotein IIb-IIIa of unactivated human platelets of various sizes.

Large (L) activated platelets exhibit greater aggregability and express more activated glycoprotein IIb-IIIa (GPIIb-IIIa) per cell and per unit surface area than small (S) activated platelets. We studied the binding of CD61 monoclonal antibody to GPIIb-IIIa on resting platelets and developed a new method for determining platelet surface area by flow cytometry. Using this method, we found that resting L platelets contain two times more GPIIb-IIIa per cell than S platelets but the same amount of GPIIb-IIIa per unit surface area. The data suggest that the greater aggregability of L platelets is likely to be due to increased activation and/ or expression of GPIIb-IIIa rather than to elevated density of unactivated GPIIb-IIIa on resting L platelets.