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Biomedical subjects

A Lichtenstein

Publications and source records attributed to A Lichtenstein.

At least 37 records · Page 2Linked to original sources
PubMed2000

Acute lung injury in two experimental models of acute pancreatitis: infusion of saline or sodium taurocholate into the pancreatic duct.

OBJECTIVE: To compare acute pulmonary changes secondary to sodium taurocholate hemorrhagic pancreatitis with those changes secondary to a less severe pancreatitis induced by saline infusion into the biliopancreatic duct. DESIGN: Prospective, randomized controlled trial. SETTING: University pulmonary laboratory. SUBJECTS: A total of 110 male Wistar rats. INTERVENTIONS: Pancreatitis was induced by either 0.5 mL of a 4% solution of sodium taurocholate (TAU group) or 0.5 mL of normal saline (SAL group) injection into the biliopancreatic duct. Data were compared with data from control (sham-operated) animals (SHAM group). MEASUREMENTS AND MAIN RESULTS: The severity of pancreatic and pulmonary injuries was evaluated 1, 3, and 8 days after the induction of acute pancreatitis by morphometric and pulmonary mechanical studies. Biliopancreatic duct pressure was measured during infusion of solutions in SAL and TAU groups. SAL and TAU groups developed an intense necrohemorrhagic pancreatitis on day 1 without differences in biliopancreatic duct pressures (134.0+/-45.1 cm H2O vs. 123.3+/-23.4 cm H2O). Acute pancreatic lesions were still intense on day 3 in the TAU group only. Pulmonary resistance in SAL and TAU groups was significantly greater than in the SHAM group on day 3 only. On day 1, there was an increase in intraalveolar edema in both groups (p < .02). There was an increase in polymorphonuclear cells in alveolar septa on day 1 only in the TAU group (p < .001). In contrast, both experimental groups presented greater values of PMN cells on day 8 compared with the SHAM group (p < .001). Both groups with pancreatitis showed an increase in alveolar distention and collapse on day 1 that persisted only in the TAU group on days 3 and 8. No deaths were observed in the control (SHAM) group. In contrast, the SAL group had lower mortality than the TAU group in the first two days (17% and 52%, respectively, p = .03). CONCLUSION: High-pressure infusion of normal saline into the biliopancreatic duct of rats results in significant pancreatic and lung alterations. These changes are worse in the presence of sodium taurocholate.

Animals↗
PubMed2000

Expression of BAX in plasma cell dyscrasias.

Several studies demonstrate that the BCL-2 and BCL-XL antiapoptotic genes are variably expressed in plasma cells of patients with multiple myeloma (MM). However, the plasma cell expression of BAX protein, their major proapoptotic partner, has not been investigated. Our initial Western blot analysis of myeloma cell extracts also suggested patient variability in the expression of BAX, which was not altered by exposure to interleukin 6. To further investigate the significance of BAX expression, we performed immunohistochemistry on archival bone marrow biopsies and compared BAX staining to BCL-2 immunostaining. Expression was first evaluated in 104 patients with reactive plasmacytosis, monoclonal gammopathy of undetermined significance/smoldering MM, or active MM. An increase (P < 0.05) in expression of both BAX and BCL-2 was detected in MM patients compared with patients with reactive plasmacytosis. Patients with monoclonal gammopathy of undetermined significance/smoldering MM had intermediate values. For correlations with outcome, expression was assessed in 43 patients at diagnosis who were treated with melphalan and prednisone; 30 at diagnosis who were treated with vincristine, Adriamycin, and dexamethasone; and 29 at relapse who were treated with second-line therapy. There was no correlation between BAX or BCL-2 expression and response to chemotherapy or duration of response or between BCL-2 expression and survival. However, patients who demonstrated extremely low plasma cell BAX expression had significantly increased survival. This was true for patients initially treated with melphalan and prednisone or vincristine, Adriamycin, and dexamethasone, as well as patients studied at relapse. BAX expression did not correlate with expression of proliferating cell nuclear antigen used as a marker of proliferation. These data indicate a myeloma-specific increase in BAX expression in plasma cells and suggest that low BAX expression identifies a cohort of patients with long survival, which is not specifically associated with low proliferating cell nuclear antigen expression.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Genetic analysis of DNA excreted in urine: a new approach for detecting specific genomic DNA sequences from cells dying in an organism.

BACKGROUND: Cell-free DNA from dying cells recently has been discovered in human blood plasma. In experiments performed on animals and humans, we examined whether this cell-free DNA can cross the kidney barrier and be used as a diagnostic tool. METHODS: Mice received subcutaneous injections of either human Raji cells or purified (32)P-labeled DNA. DNA was isolated from urine and analyzed by measurement of radioactivity, agarose gel electrophoresis, and PCR. In humans, the permeability of the kidney barrier to polymeric DNA was assessed by detection in urine of sequences that were different from an organism bulk nuclear DNA. RESULTS: In the experiments on laboratory animals, we found that approximately 0.06% of injected DNA was excreted into urine within 3 days in a polymeric form and that human-specific ALU: sequences that passed through the kidneys could be amplified by PCR. In humans, male-specific sequences could be detected in the urine of females who had been transfused with male blood as well as in DNA isolated from urine of women pregnant with male fetuses. K-ras mutations were detected in the urine of patients with colon adenocarcinomas and pancreatic carcinomas. CONCLUSIONS: The data suggest that the kidney barrier in rodents and humans is permeable to DNA molecules large enough to be analyzed by standard genetic methodologies.

Animals↗
PubMed1999

Dietary fatty acids and allergy.

The increase in the prevalence of atopic diseases has recently been linked to altered consumption of polyunsaturated fatty acids (PUFAs). As typical Western diets contain almost 10 times more linoleic acid (18:2 omega-6) than alpha-linolenic acid (18:3 omega-3), it is the metabolism of the former that predominates. Subsequently produced arachidonic acid-derived eicosanoids alter the balance of T-helper cells type 1 and type 2 thus favouring the production of immunoglobulin (Ig)E. In atopic subjects, the impact of this excessive eicosanoid production may be further strengthened as a result of changes in cyclic nucleotide metabolism exacerbated by substrate availability. Dietary omega-3 fatty acids can have marked influence on both specific and nonspecific immune responses in modifying eicosanoid production and replacing omega-6 fatty acids in cell membranes. Therefore, it is concluded that careful manipulation of dietary PUFAs may play a key role in the successful management of inflammation associated with atopic diseases.

Cell Membrane↗
PubMed1998

DNAs with unusual properties revealed by field inversion gel electrophoresis of agarose-encapsulated DNA from mammalian cells.

Distinct DNA fractions (fr-DNAs), moving separately from bulk DNA, were revealed by field inversion gel electrophoresis of DNA from intact cells lysed and deproteinized in agarose plugs. These fr-DNAs (approximately 2% of the total DNA) were ubiquitously present in nuclei of all mammalian cells studied, including human normal and tumor tissues, and showed a typical electrophoretic pattern (three bands with constant mobilities termed a-, b-, and c-DNA). Characteristic mobility shifts induced by gamma irradiation of a- and b-DNAs suggest their non-linear conformation. In fact, electron microscopy of a- and b-DNAs from Namalwa cells revealed rosette-like structures stabilized by a central protease-resistant knob. Comparative PCR analysis revealed qualitative differences between genomic fingerprints of a- and b-DNAs on the one hand and chromosomal DNA on the other. The results obtained suggest that fr-DNAs originate either from some specific chromatin regions due to non-random cleavages or from an autonomous intranuclear structure, not identified as yet.

Apoptosis↗
PubMed1998

Interleukin-6-induced inhibition of multiple myeloma cell apoptosis: support for the hypothesis that protection is mediated via inhibition of the JNK/SAPK pathway.

The mechanism by which interleukin-6 (IL-6) protects multiple myeloma (MM) plasma cells from apoptosis induced by anti-fas antibodies and dexamethasone was studied. Anti-apoptotic concentrations of IL-6 had no effect on cell-cycle distribution or activation of RAF-1 or ERK in dexamethasone- or anti-fas-treated 8226 and UCLA #1 MM cell lines. However, IL-6-dependent protection of viability correlated with an inhibition of dexamethasone- and anti-fas-induced activation of jun kinase (JNK) and AP-1 transactivation. To test the hypothesis that cytokine-induced protection was mediated through inhibition of JNK/c-jun, we also inhibited c-jun function in 8226 cells via introduction of a mutant dominant negative c-jun construct. Mutant c-jun-containing MM cells were also resistant to anti-fas-induced apoptosis but were significantly more sensitive to dexamethasone-induced apoptosis. These results support the notion that IL-6 protects MM cells against anti-fas through its inhibitory effects on JNK/c-jun but indicate protection against dexamethasone occurs through separate, yet unknown pathways.

Apoptosis↗
PubMed1998

BCL-X expression in multiple myeloma: possible indicator of chemoresistance.

Because murine myeloma plasma cells and normal human lymph node plasma cells express BCL-X, we evaluated BCL-X expression in malignant human plasma cells. BCL-X expression was detected in several human myeloma cell lines, as well as in CD38-sorted bone marrow cells obtained from some patients. Only the antiapoptotic long form of BCL-X (BCL-X-L), was detected. Because BCL-X-L expression can protect tumor cells from apoptotic death induced by chemotherapeutic agents, we tested the clinical relevance of expression in 55 archival bone marrow biopsies. The biopsies were stained by immunohistochemistry, and BCL-X expression was correlated with the subsequent response to treatment. BCL-X expression in malignant plasma cells strongly correlated with decreased response rates in patient groups treated with either melphalan and prednisone or vincristine, Adriamycin, and dexamethasone. Response rates were 83-87% in non-BCL-X-expressing cases and 20-31% in BCL-X-expressing cases. In addition, BCL-X expression was more frequent in specimens taken from patients at relapse (77%), when compared to those at initial diagnosis (29%). Further support for the association of drug resistance with BCL-X-L expression came from studies of the 8226 dox-40 cell line. This line, which expresses p-glycoprotein and serves as a model of multidrug resistance in multiple myeloma cells, demonstrated an up-regulated expression of BCL-X-L, which was relatively specific, in that BCL-2 or BAX expression was not altered. In addition, dox-40 cells demonstrated a generalized resistance to apoptosis that was induced by several different agents. These results indicate that malignant plasma cells can express BCL-X-L and that such expression may be a marker of chemoresistant disease.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

Taxol can induce phosphorylation of BCL-2 in multiple myeloma cells and potentiate dexamethasone-induced apoptosis.

We investigated the in vitro effects of paclitaxel (taxol) on multiple myeloma (MM) cells. A dose- and time-dependent induction of BCL-2 phosphorylation and apoptosis was detected in MM cell lines and two fresh clinical samples obtained from patients. A p170-overexpressing MM line and a line that did not express BCL-2 were resistant. Since phosphorylation of BCL-2 inactivates its anti-apoptotic function and could theoretically sensitize MM cells to other agents, we tested combinations of taxol and dexamethasone. Only concentrations of taxol that phosphorylated BCL-2 interacted with dexamethasone for enhanced apoptotic death. Geldanamycin, which prevented taxol-induced BCL-2 phosphorylation, also prevented the potentiated cytotoxicity.

Antibiotics, Antineoplastic↗
PubMed1998

Autologous CD34-selected blood progenitor cell transplants for patients with advanced multiple myeloma.

Fifty-five patients with advanced multiple myeloma received purified CD34-selected peripheral blood progenitor cell transplants following myeloablative chemotherapy. A median of 4.1 x 10(6) CD34 cells/kg (range 1.2-30.7) were infused after busulfan (14 mg/kg) and cyclophosphamide (120 mg/kg); granulocyte-macrophage colony-stimulating factor was used until hematopoietic recovery. Median time to neutrophils >0.5 x 10(9)/l and platelets >20 x 10(9)/l were 12 days (range 10-16 and 8-184 days, respectively). Median follow-up of survivors from the time of transplantation is 33 months (range 7 to 44 months). Thirty-one patients are alive, 19 progression-free. Median progression-free survival is 14 months. Actuarial 3-year progression-free and overall survival are 29+/-14% and 47+/-17%. CD34-selection of peripheral blood progenitor cells provides effective hematopoietic support with significant progression-free and overall survival.

Adult↗
PubMed1998

In vitro cytoreductive effects on multiple myeloma cells induced by bisphosphonates.

In a double blind randomized study, the bisphosphonate drug Pamidronate (Aredia) significantly protected Durie-Salmon stage III multiple myeloma patients from osteolytic bone disease. In the patient sub-group on salvage chemotherapy. Pamidronate treatment was also significantly associated with prolonged survival. To test if this drug could induce direct antitumor effects, we exposed myeloma cells to increasing concentrations of Pamidronate or a more potent bisphosphonate, Zoledronate. A concentration- and time-dependent cytotoxic effect was detected on four of five myeloma cell lines as well as three specimens obtained directly from myeloma patients. Zoledronate-induced cytotoxicity was significantly greater than that of Pamidronate. Cytotoxicity could not be explained by bisphosphonate-induced chelation of extracellular calcium or secondary decrease in production of the myeloma growth factor interleukin-6. Morphological examination, DNA electrophoresis and cell cycle analysis indicated that the bisphosphonate-induced cytotoxic effect consisted of a combination of cytostasis and apoptotic myeloma cell death. Enforced expression of BCL-2 protected against the apoptotic death but not against cytostasis. Most cytotoxic effects were seen between 10 and 100 microM of drug. The results suggest a possible direct anti-tumor effect in myeloma patients treated with bisphosphonates which may participate in their significantly increased survival. This hypothesis should now be further tested in clinical trials.

Antineoplastic Agents↗
PubMed1998

Long-term pamidronate treatment of advanced multiple myeloma patients reduces skeletal events. Myeloma Aredia Study Group.

PURPOSE: To determine the efficacy and safety of 21 monthly cycles of pamidronate therapy in patients with advanced multiple myeloma. PATIENTS AND METHODS: Patients with stage III myeloma and at least one lytic lesion received either placebo or pamidronate 90 mg intravenously administered as a 4-hour infusion monthly for 21 cycles. At study entry, the patients were stratified according to whether they were to receive first-line (stratum 1) or second-line (stratum 2) antimyeloma chemotherapy. Skeletal events (pathologic fracture, radiation or surgery to bone, and spinal cord compression) and hypercalcemia were assessed monthly. RESULTS: The results of the first nine previously reported cycles are extended to 21 cycles. Of the 392 randomized patients, efficacy could be evaluated in 198 who received pamidronate and 179 who received placebo. After 21 cycles, the proportion of patients who developed any skeletal event was lower in the pamidronate-group (P = .015). The mean number of skeletal events per year was less in the pamidronate-group (1.3) than in placebo-treated patients (2.2; P = .008). Although survival was not different between the pamidronate-treated group and placebo patients overall, stratum 2 patients who received pamidronate lived longer than those who received placebo (14 v 21 months, P = .041). Pamidronate was safe and well tolerated during the 21 cycles of therapy. CONCLUSION: Long-term monthly infusions of pamidronate as an adjunct to chemotherapy are superior to chemotherapy alone in reducing skeletal events in stage III multiple myeloma patients, and may improve the survival of patients on salvage therapy.

Diphosphonates↗
PubMed1997

Inhibition of lymphocyte function by head and neck carcinoma cell line soluble factors.

BACKGROUND: Immunosuppression in patients with head and neck cancer is well recognized. Previous investigations have demonstrated graded immunosuppression that becomes more pronounced as lymphocyte activity is measured closer to the primary neoplasm. In fresh tumors, a soluble factor has been identified that may partly account for the observed graded immunosuppression. OBJECTIVE: To examine the effect of soluble factors produced by head and neck sqamous cell carcinoma cell lines on the generation of lymphokine activated killer cell cytotoxicity and peripheral blood lymphocyte proliferation induced by interleukin 2, concanavalin A, and phytohemagglutinin. DESIGN: Conditioned supernatant fluids were generated in a 4-day incubation period, using 5 head and neck squamous cell carcinoma cell lines, and were assayed for the ability to inhibit the generation of lymphokine activated killer cell cytotoxicity and naive peripheral blood lymphocyte proliferation induced by interleukin 2, concanavalin A, and phytohemagglutinin. RESULTS: All conditioned supernatant fluids significantly inhibited the generation of lymphokine activated killer cell cytotoxicity relative to controls, and this inhibition was dose dependent. In contrast, supernatant fluids from a myelogenous leukemic tumor cell line, K562, and an ovarian epithelial cell line, SKOV-3, failed to inhibit cytotoxicity. Supernatant fluids conditioned with head and neck squamous cell carcinoma cell lines also profoundly inhibited the naive peripheral blood lymphocyte proliferation induced by interleukin 2, concanavalin A, and phytohemagglutinin. CONCLUSIONS: These studies demonstrate that the cell lines of head and neck squamous cell carcinoma produce soluble factors that inhibit lymphocyte function. Furthermore, these experiments suggest that the inhibition previously observed with enzymatically disaggregated fresh tumors is due to factors produced by the tumor cells rather than by other cells within the tumor matrix.

Biological Factors↗
PubMed1997

Apoptotic vs. nonapoptotic cytotoxicity induced by hydrogen peroxide.

The regulation of cellular cytotoxicity induced by hydrogen peroxide (H2O2) over a wide concentration range was assessed. Three distinct patterns were detected: the highest concentrations (> 10 mM) rapidly induced a necrotic form of death characterized by smeared patterns of DNA digestion and morphological evidence of primary cytoplasm and plasma membrane damage; In contrast, 10 and 5 mM H2O2 induced endonucleosomal DNA digestion concurrently with cytotoxicity and target cell death was associated with morphologic evidence of apoptosis. Apoptosis was inhibited by cycloheximide, emetine, aminobenzamide (ABA), aurintricarboxylic acid, and calcium depletion. The lowest concentrations of H2O2 (0.5 and 0.1 mM)-induced delayed cytotoxicity (at 24 or 48 hr), which was not associated with DNA ladder formation or morphologic evidence of apoptosis, but was inhibited by ABA. Enforced expression of BCL-2 induced resistance to 0.5 and 0.1 mM H2O2 but had no effect on cytotoxicity induced by 5 and 10 mM. Exposure of isolated nuclei to H2O2 in the absence of calcium or magnesium failed to induce endonucleosomal fragmentation. These data indicate that distinct pathways of H2O2-induced cytotoxicity can be distinguished by their different concentration dependences, and that BCL-2 can protect against some forms of H2O2-induced cytotoxicity.

Animals↗
PubMed1997

Evidence against the hypothesis that BCL-2 inhibits apoptosis through an anti-oxidant effect.

We contrasted possible protection against apoptosis afforded by either BCL-2 expression or anti-oxidant inhibitors in the same tumor target challenged by two distinct triggers of apoptosis. Exposure of L929 fibroblasts to tumor necrosis factor (TNF) or etoposide (VP-16) induced apoptotic death with similar kinetics. Enforced expression of BCL-2 significantly protected against apoptosis induced by VP-16 but had no effect against TNF-induced apoptosis. In contrast, the anti-oxidants desferrioxamine, butylated hydroxyanisol and N-acetyl cysteine all inhibited TNF-induced apoptosis in a concentration-dependent fashion. Although exposure to VP-16 resulted in a significant generation of intracellular oxyradicals, the above three anti-oxidant inhibitors had no effect on VP-16-induced apoptotic death. Interestingly, enforced expression of BCL-2 also inhibited the ability of VP-16 to generate oxy-radicals and to depress intracellular glutathione levels. These results indicate that BCL-2 can exert anti-oxidant effects but argue against the hypothesis that these effects are critical to its protection against apoptosis.

Journal Article↗
PubMed1997

Multiple myeloma cells are protected against dexamethasone-induced apoptosis by insulin-like growth factors.

Multiple myeloma cell lines express functional receptors for insulin-like growth factors (IGFs) and several cell types that make up the bone marrow microenvironment produce these cytokines. This suggests that IGFs may play a role in survival and/or expansion of the malignant clone within the marrow in patients with multiple myeloma. We tested the effects of these growth factors on myeloma cells challenged with dexamethasone. Dye exclusion and MTT assays demonstrated that both IGF-I and IGF-II protected the 8226 and dox-40 myeloma cell lines and three primary myeloma cultures from dexamethasone-induced cytotoxicity in a dose-dependent fashion. Morphologic studies of target cells and their nuclei as well as DNA electrophoresis confirmed the IGFs afforded protection against dexamethasone-induced apoptosis. Insulin also protected but was less impressive and required much higher concentrations. IGFs also protected against cycloheximide-induced apoptosis but were ineffective against serum starvation, topoisomerase II inhibitors, or anti-fas antibodies. IGF-induced protection against dexamethasone was not associated with any alteration in quantitative or qualitative expression of BCL-2, BAX or BCL-X proteins. These data indicate that insulin-like growth factors may play a role in maintenance of the malignant clone in patients with myeloma by protecting tumour cells from apoptotic death.

Animals↗
PubMed1996

Upregulated expression of BCL-2 in multiple myeloma cells induced by exposure to doxorubicin, etoposide, and hydrogen peroxide.

Enhanced expression of the antiapoptotic gene BCL-2 may participate in chemoresistance. To ascertain if multiple myeloma cells surviving exposure to chemotherapy alter their BCL-2 expression, we treated the myeloma cell lines 8226, IM-9, and U266 as well as a primary myeloma cell culture with various injurious agents. Doxorubicin, etoposide, and hydrogen peroxide consistently induced a concentration- and time-dependent upregulation of BCL-2 expression in all myeloma target cell types assayed by flow cytometry and Western blot analysis. In contrast, serum starvation, dexamethasone, and anti-fas antibodies had no effect on expression. Enhanced expression of BCL-2 was relatively selective as treatments had no effect on expression of Ig light chains, BCL-X, or actin. An reverse transcriptase-polymerase chain reaction assay showed increased levels of BCL-2 RNA in 8226 cells as early as 4 hours after treatment with doxorubicin at a time when cell recoveries were not decreased. Thus, doxorubicin stimulates BCL-2 expression in individual 8226 cells rather than simply allowing a selected survival of high BCL-2-expressing cells in culture. Doxorubicin-treated 8226 cells with upregulated BCL-2 expression were relatively resistant to a second exposure of doxorubicin. In addition, BCL-2-transfected IM-9 cells, with enhanced expression of BCL-2 which was comparable to that achieved by initial exposure to doxorubicin, were resistant to doxorubicin and etoposide cytotoxicity. These data suggest that exposure to chemotherapeutic agents may enhance BCL-2 expression in surviving myeloma cells and contribute to acquired chemoresistance.

Antineoplastic Agents↗
PubMed1996

Efficacy of pamidronate in reducing skeletal events in patients with advanced multiple myeloma. Myeloma Aredia Study Group.

BACKGROUND: Skeletal complications are a major clinical manifestation of multiple myeloma. These complications are caused by soluble factors that stimulate osteoclasts to resorb bone. Bisphosphonates such as pamidronate inhibit osteoclastic activity and reduce bone resorption. METHODS: Patients with stage III multiple myeloma and at least one lytic lesion received either placebo or pamidronate (90 mg) as a four-hour intravenous infusion given every four weeks for nine cycles in addition to antimyeloma therapy. The patients were stratified according to whether they were receiving first-line (stratum 1) or second-line (stratum 2) antimyeloma chemotherapy at entry into the study. Skeletal events (pathologic fracture, irradiation of or surgery on bone, and spinal cord compression), hypercalcemia (symptoms or a serum calcium concentration > or = 12 mg per deciliter [3.0 mmol per liter]), bone pain, analgesic-drug use, performance status, and quality of life were assessed monthly. RESULTS: Among 392 treated patients, the efficacy of treatment could be evaluated in 196 who received pamidronate and 181 who received placebo. The proportion of patients who had any skeletal events was significantly lower in the pamidronate group (24 percent) than in the placebo group (41 percent, P < 0.001), and the reduction was evident in both stratum 1 (P = 0.04) and stratum 2 (P = 0.004). The patients who received pamidronate had significant decreases in bone pain and no deterioration in performance status and quality of life. Pamidronate was tolerated well. CONCLUSIONS: Monthly infusions of pamidronate provide significant protection against skeletal complications and improve the quality of life of patients with stage III multiple myeloma.

Aged↗