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Biomedical subjects

B Bruno

Publications and source records attributed to B Bruno.

At least 55 records · Page 3Linked to original sources
PubMed1999

Rabbit antithymocyte globulin (r-ATG) plus cyclosporine and granulocyte colony stimulating factor is an effective treatment for aplastic anaemia patients unresponsive to a first course of intensive immunosuppressive therapy. Gruppo Italiano Trapianto di Midollo Osseo (GITMO)

About 30% of patients with severe aplastic anaemia (SAA) unresponsive to one course of immunosuppressive (IS) therapy with antithymocyte or antilymphocyte globulin can achieve complete or partial remission after a second IS treatment. Among various second-line treatments, rabbit ATG (r-ATG) could represent a safe and effective alternative to horse ALG (h-ALG). In a multicentre study, 30 patients with SAA (17 males and 13 females, median age 21 years, range 2-67) not responding to a first course with h-ALG plus cyclosporin (CyA) and granulocyte colony stimulating factor (G-CSF), were given a second course using r-ATG (3.5 mg/kg/d for 5 d), CyA (5 mg/kg orally from day 1 to 180) and G-CSF (5 microg/kg subcutaneously from day 1 to 90). The median interval between first and second treatment was 151 d (range 58-361 d). No relevant side-effects were observed, but one patient died early during treatment because of sepsis. Overall response, defined as transfusion independence, was achieved in 23/30 (77%) patients after a median time of 95 d (range 14-377). Nine patients (30%) achieved complete remission (neutrophils >/=2.0 x 109/l, haemoglobin >/=11 g/dl and platelets >/=100 x 109/l). The overall survival rate was 93% with a median follow-up of 914 d (range 121-2278). So far, no patient has relapsed. Female gender was significantly associated with a poorer likelihood to respond (P = 0.0006). These data suggest that r-ATG is a safe and effective alternative to h-ALG for SAA patients unresponsive to first-line IS treatment.

Adolescent↗
PubMed1999

Coexistence of normal and clonal haemopoiesis in aplastic anaemia patients treated with immunosuppressive therapy.

Cytogenetic abnormalities and paroxysmal nocturnal haemoglobinuria (PNH) phenotype are frequent findings in aplastic anaemia patients treated with immunosuppressive therapy (IST). In this study we investigated whether the appearance of clonal haemopoiesis influences patient outcome and survival. 97 patients entered this study and were followed from the onset of the disease for a median follow-up (FU) of 53 months. 93% are alive, 56% achieved complete remission, 30% partial remission, both transfusion independent, and 14% did not respond. Three groups were identified: (A) patients without evidence of emerging clones (71/97); (B) patients who acquired chromosomal abnormalities (13/97); (C) patients who showed low expression of glycosyl phosphatidylinositol anchored proteins (GPI-AP) (PNH phenotype) at presentation or later (16/97). Three patients showed both PIG-AP deficiency and chromosomal abnormalities. The actuarial survival of patients without clonal haemopoiesis (n = 71) at 6 years was 95%, for patients with chromosomal abnormalities (n = 13), 88%, and for patients with PIG-AP deficiency (n = 16), 89%. There was no difference in the probability of becoming transfusion independent in the three groups (93%, 92% and 88% respectively). This study confirmed that a proportion of severe aplastic anaemia (SAA) patients exhibit clonal markers during the time after IST, often coexisting with cytogenetically or phenotypically normal haemopoiesis. There was no significant clinical impact of these abnormalities on transfusion independence and survival at the median follow-up of 4 years.

Adolescent↗
PubMed1999

In vitro growth and quantification of early (CD33-/CD38-) myeloid progenitor cells: stem cell factor requirement and effects of previous chemotherapy.

BACKGROUND AND OBJECTIVE: All culture systems exploring the early (pre-CFU) hematopoietic compartment are generally complex, time-consuming and unsuitable for routine application. The aim of our study was to develop a stroma-free culture system to quantify early bone marrow (BM) myeloid progenitor cells. DESIGN AND METHODS: Low density, progenitor cell enriched BM cells underwent a double cytotoxic treatment with CD38 and CD33 monoclonal antibodies + rabbit complement, which depleted 99% of CFU-GM and BFU-E. Then they were cultured, both in agar and in limiting-dilution liquid culture, in the presence of 5637 cell line supernatant (containing GM-CSF, G-CSF and interleukin 1 ), stem cell factor (SCF) and interleukin 3 (IL3). RESULTS: The largest number (median 14.9 on 1x10(5) cells) and size (>50,000 cells) of myelomonocytic cell clones from CD33Eth /CD38Eth progenitors was reached after 3-4 weeks of liquid culture. SCF, but not IL3, was essential for that growth. The frequency of CD33-/ CD38- progenitors grown in liquid culture was approximately three times greater than the LTC-IC frequency in the same cell suspension. An average 93% of CD33-/CD38- progenitors displayed HLA-DR antigens and 43% generated secondary CFU-GM. In the BM of 9/10 patients, previously exposed to chemotherapy, CD33-/CD38- progenitor frequency was quite low (median 0.9 on 1x10(5) cells), in spite of normal cellularity and morphology and sustained disease remission. INTERPRETATION AND CONCLUSIONS: CD33-/CD38- progenitors can be grown and quantified in a stroma-free culture system in a relatively short time. The test can reveal long-lasting, subclinical BM damage induced by chemotherapy and could also be valuable for estimating the amount of early myeloid progenitors for transplantation purposes.

ADP-ribosyl Cyclase↗
PubMed1998

Characterization of monoclonal antibodies that recognize canine CD34.

Using a polyclonal antiserum against canine CD34, we previously found that CD34 is expressed on canine bone marrow progenitor cells in a manner analogous to that found in humans. To further characterize CD34+ cells and to facilitate preclinical canine stem cell transplant studies, monoclonal antibodies (MoAbs) were raised to CD34. A panel of 10 MoAbs was generated that reacted with recombinant CD34 and with CD34+ cell lines and failed to react with CD34- cell lines. Binding properties of five purified MoAbs were determined by BIAcore analysis and flow cytometric staining, and several MoAbs showed high affinity for CD34. Two antibodies, 1H6 and 2E9, were further characterized, and in flow cytometry studies typically 1% to 3% of stained bone marrow cells were CD34+. Purified CD34+ bone marrow cells were 1.8- to 55-fold enriched for colony-forming unit-granulocyte-macrophage and for long-term culture initiating cells as compared with bone marrow mononuclear cells, whereas CD34- cells were depleted of progenitors. Three autologous transplants were performed with CD34+ cell fractions enriched by immunomagnetic separation. After marrow ablative total body irradiation (920 cGy), prompt hematopoietic recovery was seen with transplanted cell doses of </=1.1 x 10(7) /kg that were 29% to 70% CD34+. Engraftment kinetics were similar to those of dogs previously transplanted with approximately 10- to 100-fold more unmodified autologous marrow cells. This suggests that CD34+ is a marker not only of canine bone marrow progenitors but also for cells with radioprotective or marrow repopulating function in vivo. MoAbs to CD34 will be valuable for future studies of canine hematopoiesis and preclinical studies concerning stem cell transplantation, gene therapy, and ex vivo progenitor cell expansion.

Animals↗
PubMed1998

Forscarnet vs ganciclovir for cytomegalovirus (CMV) antigenemia after allogeneic hemopoietic stem cell transplantation (HSCT): a randomised study.

This trial was designed to compare foscarnet with ganciclovir as pre-emptive therapy for CMV infection in patients undergoing allogeneic hemopoietic stem cell transplant (HSCT). Thirty-nine patients were randomized to receive foscarnet 90 mg/kg every 12 h (n = 20) or ganciclovir 5 mg/kg every 12 h (n = 19) for 15 days at the time of development of CMVAg-emia. Primary-end points of the study were (1) outcome of CMVAg-emia; (2) progression to CMV disease; and (3) side-effects of treatment. The secondary end-point was transplant-related mortality (TRM). The two groups were comparable for diagnosis, status of disease, donor type, acute graft-versus-host (aGVHD) prophylaxis, interval between HSCT and CMVAg-emia and number of CMVAg positive cells; the donor and recipient age were borderline older in the foscarnet group. Increments of serum creatinine in the foscarnet group, and cytopenia in the ganciclovir group were controlled by reducing the administered dose: in the first 15 days of therapy 9/20 foscarnet and 10/19 ganciclovir patients had a dose reduction greater than 20% (P = 0.43). Clearance of CMVAg-emia was faster in the foscarnet group although with borderline statistical significance. Failures of treatment occurred in 3/20 patients in foscarnet group vs 8/19 patients in ganciclovir group (P= 0.06): causes of failure were the need for combination therapy to control antigenemia (1/20 vs 5/19), and reactivation during treatment for 2 vs 3 patients, respectively. CMV disease was diagnosed in 1 vs 2 patients (P = 0.5) who subsequently died. The actuarial 1-year TRM was 25 vs 12%, respectively (P = 0.3). This study suggests that foscarnet and ganciclovir are both effective for pre-emptive therapy of CMVAg-emia, although the number of failures would seem to be slightly higher in the ganciclovir patients. Side-effects are seen in both groups and can be managed with appropriate dose reduction.

Adolescent↗
PubMed1998

Comparable TNF-alpha, IFN-gamma and GM-CSF production by purified normal marrow CD3 cells in response to horse anti-lymphocyte and rabbit antithymocyte globulin.

In vitro priming of T cell with horse antilymphocyte globulin (HALG) results in cytokine release, and this has been associated with its clinical efficacy in patients with severe aplastic anaemia (SAA). Rabbit antithymocyte globulin (RATG) has been studied less extensively. In this study we compare the in vitro priming effect of HALG and RATG on purified normal marrow T cells: end-points of the study were 1) levels of TNF-alpha (TNF-alpha), IFN-gamma (IFN-gamma) GM-CSF in T cell supernatants, and 2) effect of T cell supernatants on colony formation with or without exogenous GM-CSF TNF-alpha, IFN-gamma and GM-CSF levels were comparable for HALG, RATG and phytohaemagglutinin (PHA). T cell supernatants showed comparable enhancement of colony formation in the presence of recombinant human GM-CSF (rhGM-CSF) and supported colony forming unit granulomacrophage (CFU-GM) growth in the absence of growth factor. This study shows that horse and rabbit derived ALG/ATG and PHA have a comparable in vitro priming effect on T cells: both agents should probably be tested for their clinical efficacy in SAA patients.

Anemia, Aplastic↗
PubMed1998

Synthesis and biological evaluation of 5H-indolo [3,2-b][1,5]benzothiazepine derivatives, designed as conformationally constrained analogues of the human immunodeficiency virus type 1 reverse transcriptase inhibitor L-737,126.

In the presence of sodium hydride, reaction of aryl-disulphides with ethyl esters of indole-2-carboxylic acids furnished ethyl 3-arylthioindole-2-carboxylates, which were cyclized intramolecularly to afford 5H-indolo[3,2-b][1,5]benzothiazepin-6(7H)-ones or hydrolysed in alkaline medium to give 3-arylthioindole-2-carboxylic acids. These acids, also obtained by the action of aryldisulphides on indole-2-carboxylic acids, afforded tetracyclic 5H-indolo [3,2-b][1,5]benzothiazepin-6(7H)-ones upon treatment with EDCI-DMAP. Transformation of cyclic sulphides into the required sulphones was achieved by treatment with hydrogen peroxide or with m-chloroperbenzoic acid. The title derivatives are conformationally constrained analogues of the potent human immunodeficiency virus type 1 (HIV-1) reverse transcriptase inhibitor 3-benzene-sulphonyl-5-chloroindole-2-carboxamide (L-737, 126). Although the indolobenzothiazepine derivatives, as well as the indolyl aryl sulphones used for their synthesis, were endowed with anti-HIV-1 activities in the submicromolar and micromolar range, none of them proved more potent than L-737,126.

Anti-HIV Agents↗
PubMed1997

Multicyclic, dose-intensive chemotherapy supported by hemopoietic progenitors in refractory myeloma patients.

Attempts to increase dose intensity have been hampered by hematologic toxicity. To address this issue, we designed a study to determine whether the reinfusion of PBPC significantly reduces the toxicity of multicyclic dose-intensive chemotherapy. Thirty refractory patients, median age 63, received CY 3 g/m2 plus melphalan 60 mg/m2 followed by PBPC and G-CSF (CM regimen). CY (at day 0) and G-CSF were used to mobilize PBPC harvested by a single leukapheresis at day 10. Melphalan was infused at day 11. PBPC were kept unprocessed at 4 degrees C for 48 h and reinfused at day 12. This regimen was repeated three times every 6 months. Outcomes were compared with those of 30 similar patients treated with melphalan 30 mg/m2 followed by G-CSF only, and repeated every 2 months for a total of six cycles. In patients receiving CY plus melphalan followed by PBPC reinfusion, the median duration of neutropenia (ANC < 500/microliters) and thrombocytopenia (platelets < 2500 microliters) was only 5 and 2 days respectively, and did not increase after the subsequent courses. Hematologic toxicity was quite similar to that observed after melphalan 30 mg/m2 plus G-CSF. The CM regimen was followed by 30% complete remission and 86% response > 50%, melphalan 30 mg/m2 by no complete remissions and 38% response > 50%. Patients receiving CM regimen showed a longer progression-free survival (22 vs 10 months, P < 0.01). The dose intensity of melphalan can be doubled by reinfusing PBPC without increasing toxicity. The combination of CY and melphalan followed by PBPC improves response rate and outcome when compared to low-dose melphalan.

Aged↗
PubMed1996

Combined differentiating therapy for myelodysplastic syndromes: a phase II study.

An in vitro synergism between different inducers of AML cell differentiation has been previously observed. Therefore, we treated 53 myelodysplastic (MDS) patients with a low dose combination of cis-retinoic acid (cRA, 20-40 mg/day) and 1,25 alpha (OH)2 cholecalciferol [(OH)2D3, 1-1.5 micrograms/day] +/- intermittent 6-thioguanine (30 mg/m2/day). The latter was reserved for patients with bone marrow (BM) blast excess (> or = 5%). The treatment was well tolerated, without major toxicity. Among 25 patients with BM blasts less than 5%, we observed one complete, eight partial and four minor responses (response rate 52%) with a median response duration of 8 months (2 +/- 24). Median survival, which did not correlate with response, is projected at 76 months. Thirty-one patients with BM blast excess (> or = 5%), including three of the previous group who progressed to refractory anemia with excess of blasts (RAEB), were treated with the three-drug protocol. One complete, 12 partial and six minor responses were obtained (response rate 61%) with a median response duration of 6 months (2-29+). A significant difference in survival (P < 0.005) was observed between the 19 responders (median 25 months) and the 12 non-responders (median 9 months). A reduction in the transfusion need was observed in 41% of the transfusion-dependent patients with blast excess and in 53% of those without blast excess. Therefore, combined differentiating therapy seems more effective than previously reported single agent treatments and should be considered for a larger randomized study to assess its actual impact on survival of MDS patients.

Aged↗
PubMed1995

Retinoic acid inhibits the growth of human myeloma cells in vitro.

Retinoic acid has been shown to induce growth inhibition in a variety of cell types including human myeloma cell lines. Bone marrow plasma cells from 31 multiple myeloma (MM) patients were cultured to investigate the activity of 13-cis-retinoic acid (cRA), all-trans-retinoic acid (tRA), interferon-alpha (IFN-alpha), interferon-gamma (IFN-gamma), and dexamethasone (DEX), alone or in combination, on in vitro proliferation and immunoglobulin (Ig) secretion. Both cRA and tRA inhibited proliferation: the labelling index (LI) of treated cultures/controls, was 0.47 +/- 0.05 (mean +/- standard error mean, M +/- SEM) P < 0.0001, and 0.67 +/- 0.04 (M +/- SEM), P < 0.0001, respectively. The inhibitory effect of cRA was significantly superior to tRA (P = 0.0129) and IFN-alpha, similar to IFN-gamma and DEX. The combinations of cRA + IFN alpha, tRA + IFN-gamma, tRA + DEX did not show any synergistic effect on myeloma proliferation. In contrast, the combination cRA + DEX (0.29 +/- 0.04, M +/- SEM) markedly increased the effect of both cRA and DEX used as single agents. Ig synthesis was not significantly affected by CRA, tRA, IFN-gamma and the combination tRA + IFN-gamma. As expected, only IFN-alpha (P = 0.002) and DEX (P < 0.001) inhibited Ig production. The combinations cRA + IFN-alpha, cRA + DEX and tRA + DEX decreased Ig secretion to the same extent as IFN-alpha and DEX alone respectively. In conclusion, our data indicate that tRA and especially cRA strongly inhibited plasma cell proliferation but had no effect on Ig synthesis. The combination of cRA + DEX showed the highest degree of inhibitory activity of all cytokines, alone or in combination.

Antibodies, Neoplasm↗
PubMed1995

Interferon-gamma in multiple myeloma.

Biological heterogeneity is a characteristic of multiple myeloma. A dysregulated cytokine network underlies the various phases of the disease. Numerous cytokines, either promoting or inhibiting plasma cell growth, are involved in tumor control. Interferon-gamma (IFN-gamma) showed the most powerful inhibiting activity on myeloma cell proliferation. This effect was demonstrated on IL-6 dependent myeloma cell lines, but not on IL-6 independent ones. It was also evident on fresh explanted bone marrow myeloma cells. The antiproliferative effect of IFN-gamma seems mainly due to the inhibition of IL-6, the central myeloma growth factor. IL-6 inhibition may occur at various levels: a downregulation of IL-6 receptor has been reported, and also a block of the IL-6 signal transduction pathway via interaction with cytoplasmic proteins such as p91 has been suggested. Our findings showed that IFN-gamma strongly inhibited myeloma cell proliferation to the same extent as dexamethasone (DEX), whereas interferon-alpha (IFN-alpha) inhibited Ig secretion. The combined use of interferons (IFNs) showed inhibitory activities both on proliferation and Ig synthesis that paralleled the effects of DEX. In some cases, IFN-gamma was also shown to augment monoclonal immunoglobulin secretion suggesting a possible differentiating activity on plasma cells. The in vitro data encouraged pilot studies to evaluate the in vivo antitumor effects of IFN-gamma.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Division↗
PubMed1994

Recombinant interferon-gamma inhibits the in vitro proliferation of human myeloma cells.

Interferon-alpha (IFN-alpha), interferon-gamma (IFN-gamma) and dexamethasone (DEX) have shown anti-tumour effects in multiple myeloma (MM) cells. Bone marrow plasma cells from 39 MM patients were cultured to clarify the intensity and specific activity of each compound on bromo-deoxyuridine (BrdUrd) uptake and immunoglobulin (Ig) secretion. BrdUrd uptake was inhibited by recombinant human IFN-gamma (100 U/ml) and by DEX (10(-6) M). The stimulation index (StI), i.e. labelling index (LI) of treated samples/controls, was 0.49 +/- 0.09 (mean +/- standard error of the mean, M +/- SEM), P = 0.0003, and 0.52 +/- 0.07 (M +/- SEM), P < 0.0001, respectively. Ig secretion was reduced by IFN-alpha (100 U/ml) and DEX. The secretion index (SI), i.e. Ig quantitation of treated samples/controls, was 0.04 (M +/- SEM), P < 0.0001, and 0.52 +/- 0.04 (M +/- SEM), P < 0.0001, respectively. Finally, IFN-gamma inhibits BrdUrd uptake only and IFN-alpha secretion only. In 18 patients the simultaneous addition of IFN-alpha plus IFN-gamma mainly parallel the effect of IFN-gamma on BrdUrd uptake and IFN-alpha on secretion, but not result in any additive or synergistic effect, though both BrdUrd uptake and Ig secretion were decreased to about the same extent as with DEX. These data indicate that the combination of IFN-alpha plus IFN-gamma and DEX are the strongest inhibitors of both BrdUrd uptake and secretion. Since IFN-alpha and IFN-gamma appear to have a different mechanism of action, their combined use could be considered as a possible new treatment strategy.

Bone Marrow↗
PubMed1994

Generation of anti-tumour activity by OKT3-stimulation in multiple myeloma: in vitro inhibition of autologous haemopoiesis.

T cells in multiple myeloma (MM) patients are highly susceptible to activation with the anti-CD3 monoclonal antibody (mAb) OKT3. When short-term OKT3 stimulation is carried out on bone marrow mononuclear cells (BMMC), large numbers of CD3+ CD25+ HLA-DR+ cells are rapidly generated and autologous malignant plasma cells are killed. OKT3 may thus be exploited in autologous bone marrow transplantation (ABMT) to purge residual plasma cells and simultaneously activate T cells to induce graft-versus-leukemia-like (GVL-like) activity upon reinfusion. However, the possible impact of ex-vivo short-term OKT3 stimulation on haematological recovery is unknown. The aim of this work was to investigate the effect of OKT3 stimulation in vitro on autologous haemopoietic progenitor cells (HPC) of MM patients. Colony formation by granulocyte-macrophage progenitor cells (granulocyte-macrophage colony-forming units, CFU-GM) was highly suppressed, although supernatants of OKT3-activated T cells contained up to 2,500 pg/ml of granulocyte-macrophage colony-stimulating factor (GM-CSF). T cell depletion completely prevented this suppression. Neutralizing antibodies against TNF-alpha, TNF-beta and IFN-gamma (which are also produced by OKT3-activated MM T cells) did not prevent it, and Transwell cultures showed that cell-to-cell contact was the main mechanism involved. OKT3-activated T cells also suppressed erythroid burst-forming units (BFU-E) and CFU-GM generation from HPC responsible for long-term maintenance of in vitro myelopoiesis. When tested on normal allogeneic BM, MM supernatants of OKT3-stimulated BMMC partially suppressed the generation of day 7 CFU-GM, but had no effect on day 14 CFU-GM. These data indicate that short-term stimulation of BMMC with OKT3 can be used to generate anti-tumour effector T cells for autologous adoptive immunotherapy. It is not a feasable approach for ex-vivo purging and activation procedures in ABMT because of its potent inhibition of autologous haemopoiesis.

Bone Marrow Cells↗
PubMed1992

Glucocorticoid stabilization of actin filaments: a possible mechanism for inhibition of corticotropin release.

The mechanism by which glucocorticoids induce various cellular responses in different tissues is only partially understood. Here we demonstrate that glucocorticoids stabilize the actin cytoskeleton of several cell types, as revealed by increased resistance of actin filaments to the disrupting effect of cytochalasin and by visible thickening of actin filament bundles. These effects require several hours to develop, require protein synthesis, and are accompanied by increased expression of the actin-binding protein caldesmon. These data may help to explain why glucocorticoids inhibit corticotropin release from pituitary cells, if interpreted in terms of the current idea that an actin filament "barrier" modulates exocytotic secretion in various cell types. In support of this idea, we find that in "model" corticotrophs (AtT-20 cells), glucocorticoids stabilize actin filaments and inhibit corticotropin release with similar potencies. Furthermore, we show here that glucocorticoid inhibition is overcome by exposing AtT-20 cells to concentrations of cytochalasin B or D that disrupt their stabilized actin filaments. On the other hand, our freeze-etch electron microscopy of AtT-20 cells has shown that actin filaments do not, in fact, create a dense submembranous barrier that might prevent corticotropin secretory droplets from discharging; instead, they form open networks near the membrane that appear to hold secretory droplets in their interstices. We propose that the delicate physical crosslinks maintaining this actin-mediated membrane "docking" of secretory droplets may need to disconnect in order to permit corticotropin discharge and that these crosslinks may be stabilized along with the actin filaments in dexamethasone-treated cells.

Actin Cytoskeleton↗
PubMed1989

[Monoclonal anti-AFP immunoscintigraphy of human hepatocellular carcinoma. Influence of biological, anatomical and vascular factors].

The actual interest of immunoscintigraphy for the detection of alphafetoprotein-producing liver tumors was investigated by both visual examination and quantitative analysis in 61 patients with either hepatocellular carcinoma (39 patients, group I), secondary liver cancer (11 patients, group II), or non tumoral liver (9 cirrhosis, 2 healthy liver, group III): All patients received injections of 123I-anti-alphafoetoprotein monoclonal antibodies and planar scans were performed after 28 hours. Only 18 out of 39 hepatocellular carcinoma-bearing patients had a positive scan (46 p. 100). Such a moderate sensibility was due to a striking inhibitory influence of cirrhosis: the positivity rate was 6/24 and 12/15 respectively when hepatocellular carcinoma was and was not associated with cirrhosis (p less than 0.01). Specificity was also moderate (55 p. 100) for detection of hepatocellular carcinoma in tumor-bearing patients (group I and II). In the absence of cirrhosis, the intensity of the tumoral uptake was highly correlated with high serum alphafoetoprotein level (p less than 0.001) and tumor arterial hypervascularization (p less than 0.01). Anti-alphafoetoprotein monoclonal antibody uptake by the extratumoral liver was found to be very specific of hepatocellular carcinoma since it was high in 23 out of 39 patients of group I but in only 1 out of 22 in groups II and III (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Immunocytochemistry of calciosomes in liver and pancreas.

Calciosomes are small cytoplasmic vacuoles identified in various nonmuscle cell types by their content of protein(s) similar to calsequestrin (CS), the Ca2+ storage protein of the muscle sarcoplasmic reticulum (SR). These entities have been interpreted as the "primitive" counterpart of the SR, and suggested to be the organelle target of inositol-1,4,5-triphosphate action (Volpe, P., K. H. Krause, S. Hashimoto, F. Zorzato, T. Pozzan, J. Meldolesi, and D. P. Lew. Proc. Natl. Acad. Sci. USA. 85:1091-1095). Immunoperoxidase and immunogold experiments carried out in both thick and ultrathin cryosections of rat hepatocytes and pancreatic acinar cells by using antimuscle CS antibodies revealed a specific labeling widely distributed in the entire cytoplasm, while nuclei were negative. Individual calciosomes appeared as small (105 nm) membrane-bound vacuoles intermingled with, and often apposed to ER cisternae and mitochondria. Other calciosomes were scattered in the Golgi area, in between zymogen granules and beneath the plasma membrane. The cumulative volume of the CS-positive organelles was measured to account for the 0.8 and 0.45% of the cytoplasm in liver and pancreas cells, respectively. The real total volume of the calciosome compartment is expected to be approximately twice as large. In hepatocytes, structures similar to CS-positive calciosomes were decorated by antibodies against the Ca2+ ATPase of muscle SR, while ER cisternae were not. By dual labeling, colocalization was revealed in 53.6% of the organelles, with 37.6% positive for the ATPase only. CS appeared preferentially confined to the content, and the Ca2+ ATPase to the contour of the organelle. The results suggested a partial segregation of the two antigens, reminiscent of their well-known segregation in muscle SR. Additional dual-label experiments demonstrated that hepatic calciosomes express neither two ER markers (cytochrome-P450 and NADH-cytochrome b5 reductase) nor the endolysosome marker, luminal acidity (revealed by 3-[2,4-dinitroanilino]-3'-amino-N-methyl dipropylamine). Calciosomes appear as unique cytological entities, ideally equipped to play a role in the rapid-scale control of the cytosolic-free Ca2+ in nonmuscle cells.

Animals↗