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Biomedical subjects

K M Skubitz

Publications and source records attributed to K M Skubitz.

At least 37 records · Page 2Linked to original sources
PubMed1998

Mechanism of transient dyspnea induced by pegylated-liposomal doxorubicin (Doxil).

While mucositis and hand-foot syndrome are the main limiting toxicities of pegylated-liposomal doxorubicin, a small proportion of patients develop transient dyspnea at the initiation of drug infusion. Of the first 35 patients in a phase II study of pegylated-liposomal doxorubicin, three developed dyspnea, two low back pain and two pain at the site of tumor, within 1-5 min after starting the pegylated-liposomal doxorubicin infusion. The symptoms resolved within 5-15 min of stopping the infusion. In each case, the infusion was restarted without adverse effect. The mechanism of these symptoms is unclear. Because the dyspnea was reminiscent of that seen with hemodialysis neutropenia, complete blood counts were obtained in four of these patients approximately 2 min after the onset of symptoms. In all four patients, relative neutropenia was present (ANC 35, 3, 24 and 46% of pretreatment) that resolved by the end of the pegylated-liposomal doxorubicin infusion. Pegylated-liposomal doxorubicin stimulated neutrophil adhesion to human umbilical vein endothelial cells in vitro at concentrations predicted to be present in plasma during the initiation of treatment. Thus, pegylated-liposomal doxorubicin can induce an increase in neutrophil adhesion directly. We conclude that one mechanism of pegylated-liposomal doxorubicin-induced acute dyspnea is a transient sequestration of neutrophils in the pulmonary circulation, resulting in a decrease in compliance and associated dyspnea. In the patients in this study, these symptoms were transient, mild and not life threatening. Pegylated-liposomal doxorubicin is generally well tolerated and we do not routinely use premedications in patients receiving pegylated-liposomal doxorubicin.

Adult↗
PubMed1997

CD50 monoclonal antibodies inhibit neutrophil activation.

The constitutive high expression of CD50 (ICAM-3) on resting leukocytes, coupled with the observation that CD50 is the primary LFA-1 ligand on resting T cells, suggests that CD50 may be an important LFA-1 ligand in the initiation of the immune/inflammatory response. CD50 mAbs have been reported to increase homotypic adhesion of lymphocytes, and lymphocyte adhesion to HUVEC and extracellular matrix proteins. In this study, the effects of CD50 mAbs on neutrophil activation were examined. CD50 mAbs were found to inhibit neutrophil adhesion induced by FMLP and 12-O-tetradecanoyl-phorbol-13-acetate to resting and TNF-activated HUVEC. CD50 mAbs also inhibited neutrophil adhesion stimulated by CD66a, CD66b, CD66c, and CD66d mAbs to HUVEC. CD50 mAbs inhibited the up-regulation of CD11b/CD18 to the neutrophil surface, and the down-regulation of surface CD62L expression. The potential contribution of src family kinases to the previously described tyrosine kinase activity associated with CD50 in neutrophils was also examined. hck and lyn were found to account for much of the tyrosine kinase activity associated with CD50 in neutrophils. The data indicate that CD50 in neutrophils functions not only as a potential ligand for LFA-1, but also regulates the surface expression and activity of CD11b/CD18 and CD62L. In contrast to the effects in lymphocytes, CD50 appears to function as a negative regulator of neutrophil activation.

Antibodies, Monoclonal↗
PubMed1997

A phase I study of ambulatory continuous infusion paclitaxel.

Chemotherapy given by continuous infusion may have different toxicity profiles and efficacy than when given by bolus administration. Thirty-one patients with refractory tumors entered a phase I trial in which paclitaxel was administered for 7 days by continuous infusion every 28 days. Only one patient required hospitalization for treatment, because of an initial poor performance status, and most carried out normal activities on an ambulatory basis. After the first three patients, patients were entered in cohorts of five with the starting dose of 120 mg/m2. Each subsequent cohort was begun at a dose 10% higher than the previous cohort. Later courses within each cohort were increased 10% in an individual patient, if toxicity allowed. Nausea was rare. Of 15 patients with a soft tissue sarcoma refractory to doxorubicin, dacarbazine, ifosfamide, and etoposide, there were: one partial response (PR), five stable diseases and eight progressive; one patient was not evaluable for response. The PR occurred in a patient with a very aggressive sarcoma and very bulky disease, and was maintained for more than 1 year. We conclude that paclitaxel given by ambulatory continuous i.v. infusion is well tolerated with a maximally tolerated starting dose of 160 mg/m2.

Adult↗
PubMed1996

CD63 associates with tyrosine kinase activity and CD11/CD18, and transmits an activation signal in neutrophils.

As a member of the tetraspan family, it has been hypothesized that CD63 may be associated with signal transduction; however, its role in leukocyte function is unknown. To examine the potential ability of CD63 to activate neutrophils, the effects of five CD63 mAbs, AHN-16, -16.1, -16.2, -16.3, and -16.5, were examined for their ability to alter neutrophil adhesion to HUVEC monolayers. These CD63 Abs increased neutrophil adhesion to resting and TNF-stimulated HUVEC monolayers. This increase in neutrophil adhesion caused by CD63 Abs was blocked by a CD18 Ab and was associated with up-regulation of CD11/CD18 and down-regulation of CD62L on the neutrophil surface. CD11/CD18 was also found to be associated with CD63. This increase in neutrophil adhesion required physiologic extracellular calcium concentrations at or near the time of CD63 Ab binding. The incubation of CD63 Abs with cells in the absence of calcium for 10 min before repletion of calcium resulted in no increase in neutrophil adhesion. Protein kinase activity was detected in neutrophils associated with CD63. Most of the protein kinase activity associated with these Ags was tyrosine kinase activity, with a lesser amount of threonine and serine kinase activities. Src family kinases Lyn and Hck accounted for much of the associated tyrosine kinase activity. The data suggest that CD63 Ab binding to the neutrophil surface triggers a transient activation signal that requires extracellular calcium and regulates the adhesive activity of CD11/CD18. Associated protein kinase activity may play a role in signal transduction by CD63 to regulate other cell functions.

Animals↗
PubMed1996

A novel recognition site on laminin for the alpha 3 beta 1 integrin.

Synthetic peptide GD-2 is a sequence of amino acids derived from the carboxy-terminal long arm of the A chain of laminin. Previous studies have shown that peptide GD-2 promotes the adhesion of human squamous cell carcinoma (SCC) cells as well as a variety of other cell lines. In this study, we attempted to identify the receptor that SCC cells use to adhere to peptide GD-2. Monoclonal antibodies (mAbs) against a human SCC cell line were generated. One of these mAbs, ASC-1, bound to the surface of SCC cells as determined by flow cytometry. This mAb inhibited SCC cell adhesion to peptide GD-2 and laminin, but not fibronectin or type IV collagen, suggesting that mAb ASC-1 binds to the SCC receptor for the peptide GD-2 sequence of laminin. MAb ASC-1 immunoprecipitated a complex composed of two components of 135 and 116 kDa. Immunoadsorption of ASC-1-binding material from the SCC cell extract by incubation with mAb ASC-1 resulted in the removal of the alpha 3 beta 1 integrin from the extract. Immunohistochemical staining of tissue from a normal human tongue and from a patient with SCC of the tongue revealed that mAb ASC-1 stained the surface of epithelial cells that were in contact with the basement membrane, as well as those cells located two to three layers above the basement membrane. This mAb also stained blood vessels in the squamous tissue. This staining pattern was identical to that observed when the same tissues were stained by a mAb against the alpha 3 integrin subunit. In summary, by use of a new mAb, ASC-1, that recognizes the alpha 3 beta 1 integrin, we have determined that the alpha 3 beta 1 integrin mediates SCC cell adhesion to the peptide GD-2 sequence within laminin.

Amino Acid Sequence↗
PubMed1996

CD66a, CD66b, CD66c, and CD66d each independently stimulate neutrophils.

Four members of the carcinoembryonic antigen family, CD66a, CD66b, CD66c, and CD66d, are expressed on human neutrophils. In neutrophils these proteins are activation antigens in that their surface expression is increased following stimulation. To examine their potential role in neutrophil signaling, the effects on neutrophil adhesion to human umbilical vein endothelial cells of a panel of well-characterized CD66 mAbs was tested. CD66a, CD66b, CD66c, and CD66d antibodies each increased neutrophil adhesion to human umbilical vein endothelial cell monolayers. This increase in neutrophil adhesion caused by CD66 antibodies was blocked by a CD18 antibody and associated with up-regulation of CD11/CD18 on the neutrophil surface. This increase in neutrophil adhesion required physiological extracellular calcium concentrations at or near the time of CD66 antibody binding to the neutrophil. The incubation of CD66 antibodies with neutrophils in the absence of calcium for 10 min before repletion of calcium resulted in no increase in neutrophil adhesion. The data suggest that CD66a, CD66b, CD66c, and CD66d antibody binding to the neutrophil surface triggers a transient activation signal that requires extracellular calcium and regulates the adhesive activity of CD11/CD18. Sequential desensitization experiments indicated that CD66a, CD66b, CD66c, and CD66d can each independently transmit signals in neutrophils.

Antibodies, Monoclonal↗
PubMed1996

Oral glutamine to prevent chemotherapy induced stomatitis: a pilot study.

Mucositis is a common toxicity of cancer chemotherapy. Glutamine appears to be the major energy source for intestinal epithelium, and animal studies have suggested that dietary supplementation with glutamine may protect the gut from both radiation and chemotherapy. Patients experiencing stomatitis after a course of chemotherapy were offered the opportunity to enter the current study if no clinical parameters precluded receiving the same chemotherapy doses during the next course of treatment. Patients received the same chemotherapy regimen as during the previous treatment but in addition received a suspension of L-glutamine, 4 gm swish and swallow twice a day, from day 1 of chemotherapy for 28 days or for 4 days past the resolution of any post-chemotherapy mucositis. Twelve patients receiving doxorubicin, 1 receiving etoposide, and 1 receiving ifosfamide, etoposide, and carboplatinum were entered into the study. The maximum grade (CALGB criteria) of mucositis decreased in 12 of 14 patients with glutamine supplementation (median score 2A vs 0.5, p < 0.001). Similarly, after glutamine supplementation, the total number of days of mucositis was decreased in 13 of 14 patients (2.7 +/- 0.8 (mean +/- SEM) vs 9.9 +/- 1.1, p > or = 0.001). Thirteen of the 14 patients felt that the mucositis was less severe with the addition of glutamine. No change in the nadir neutrophil count was noted with glutamine, and no toxicity of glutamine was observed. We conclude that oral supplementation with glutamine can significantly decrease the severity of chemotherapy-induced stomatitis, an important cause of morbidity in the treatment of patients with cancer. Glutamine supplementation in patients receiving therapy for cancer warrants further study.

Acquired Immunodeficiency Syndrome↗
PubMed1995

CD66 family members are associated with tyrosine kinase activity in human neutrophils.

The granulocyte activation Ags, CD66a, CD66b, CD66c, and CD66d, are expressed at low levels on resting blood granulocytes, but their surface expression is up-regulated following stimulation. CD66a, in contrast to CD66b and CD66c which are anchored to the membrane via a glycosyl-phosphatidylinositol linkage, is a transmembrane protein with a cytoplasmic domain. We have previously reported that CD66a is phosphorylated in human neutrophils, largely on tyrosine, with a lower level of phosphoserine. We have now found that CD66a undergoes a rapid increase in phosphorylation following stimulation with FMLP, platelet-activating factor, and 12-O-tetradecanoyl-phorbol-13-acetate. This increase in phosphorylation was transient, with maximal phosphorylation observed by 1 min and a return to base line by 5 min following stimulation. Protein kinase activity was detected in neutrophils associated with CD66a, CD66b, and CD66c. Most of the protein kinase activity associated with these Ags was tyrosine kinase activity, with a lesser amount of threonine and serine kinase activities. Lyn and Hck accounted for much of the associated tyrosine kinase activity. The data suggest that phosphorylation of CD66a on tyrosine by an associated tyrosine kinase may play a role in the function of CD66a. In addition, associated tyrosine kinase activity may play a role in signal transduction from CD66a, CD66b, and CD66c to regulate other cell functions.

Antigens, CD↗
PubMed1995

CD50 (ICAM-3) is phosphorylated on tyrosine and is associated with tyrosine kinase activity in human neutrophils.

CD50 (ICAM-3) is expressed at a high level on resting blood granulocytes, monocytes, and lymphocytes. The constitutive high expression of CD50 on resting leukocytes suggests that it is an important LFA-1 ligand in the initiation of the immune/inflammatory response. Using a radiolabeling technique initially designed to detect ecto-protein kinase activity, we found that CD50 mAbs immunoprecipitated a approximately 125- to 170-kDa phosphoprotein from human neutrophils. Phosphorylation was increased after stimulation with the chemotactic agent FMLP, platelet-activating factor, 12-O-tetradecanoyl-phorbol-13-acetate, and the calcium ionophore A23187. This increase in phosphorylation was transient with the maximal phosphorylation, being observed by 1 min. Phosphoamino acid analysis revealed that CD50 contained predominantly phosphotyrosine. Although this assay system was designed initially to detect ecto-protein kinase activity, subsequent studies have shown that membrane proteins can be phosphorylated on the cytoplasmic domain under these conditions. When CD50 was immunoprecipitated from solubilized neutrophils, protein tyrosine kinase activity associated with CD50 was detected in the immunoprecipitate. The data suggest that phosphorylation of CD50 on tyrosine by an associated tyrosine kinase plays a role in the function of CD50.

Antigens, CD↗
PubMed1995

Pulmonary toxicity of continuous infusion 5-fluoro-2'-deoxyuridine.

This report describes a patient who developed pulmonary toxicity, manifest by dyspnea on exertion, a low pO2, a normal FEV1 and FVC, and a low DLCO while receiving 5-fluoro-2'-deoxyuridine (FUDR) by intermittent continuous i.v. infusion. No other cause of his low DLCO could be identified. The dyspnea on exertion and DLCO improved gradually after the FUDR was discontinued. This case was felt to represent a previously undescribed toxicity of the continuous i.v. infusion of FUDR.

Aged↗
PubMed1995

Nonlethal adherence to human neutrophils mediated by Dr antigen-specific adhesins of Escherichia coli.

Uropathogenic Escherichia coli strains express a variety of adhesins, including members of the Dr adhesin family such as the Dr hemagglutinin, AFAI, and AFAIII. Certain E. coli adhesins (e.g., type 1 and S fimbriae) are known to mediate adherence to human polymorphonuclear leukocytes (PMNs). The receptor on erythrocytes for Dr family adhesins, decay accelerating factor, is also present on PMNs. To determine whether Dr family adhesins mediate adherence to PMNs and to characterize the specificity and consequences of such adherence, we studied agglutination of PMNs and adherence to PMNs by recombinant E. coli strains expressing various mannose-resistant or mannose-sensitive adhesins, in the presence or absence of inhibitors of adherence. Dr family adhesins, like type 1 fimbriae, mediated concentration-dependent adherence to PMNs. Adherence to PMNs was mannose sensitive for type 1 fimbriae but mannose resistant for Dr family adhesins. Chloramphenicol inhibited PMN adherence for the Dr hemagglutinin with the same potency as that with which it inhibited hemagglutination, but it was inactive against PMN adherence and hemagglutination mediated by other members of the Dr adhesin family. In contrast to PMN adherence mediated by type 1 fimbriae, adherence mediated by the Dr hemagglutinin did not lead to significantly increased bacterial killing. These data suggest that Dr family adhesins mediate a novel pattern of adherence to PMNs, probably by recognizing decay accelerating factor, with minimal consequent bacterial killing.

Agglutination↗
PubMed1995

Clusterin promotes the aggregation and adhesion of renal porcine epithelial cells.

The function of clusterin, a heterodimeric glycoprotein markedly induced in renal and other organ injuries, is unclear. Since renal injury is accompanied by alterations in cell attachment, it is possible that clusterin functions to promote cell-cell and cell-substratum interactions. In this study, a single cell suspension of renal epithelial (LLC-PK1) cells was treated with purified human clusterin, resulting in time- and dose-dependent cell aggregation. Electron microscopy of the cell aggregates demonstrated cell junction and lumen formation. To determine the effect of clusterin on cell adhesion, tissue culture plates were coated with clusterin, fibronectin, PBS, or albumin. Clusterin and fibronectin promoted cell adhesion to the same extent. The adhesion to clusterin was dose dependent and specific, as a monoclonal antibody against clusterin inhibited cell adhesion to clusterin but not fibronectin. Perterbations of the cytoskeleton may underlie the alterations in cell attachment which occur in renal injury. Induction of clusterin mRNA was seen after disruption of both microtubules and microfilaments and after inhibition of cell-substratum interactions. In conclusion, clusterin is a potent renal epithelial cell aggregation and adhesion molecule. We speculate that clusterin functions to promote cell-cell and cell-substratum interactions which are perturbed in the setting of renal injury, thereby preserving the integrity of the renal epithelial barrier.

Animals↗
PubMed1994

CD31 (PECAM-1), CDw32 (Fc gamma RII), and anti-HLA class I monoclonal antibodies recognize phosphotyrosine-containing proteins on the surface of human neutrophils.

Although most studies of protein phosphorylation have focused on intracellular reactions, studies have provided evidence for the existence of ectoprotein kinase activity on the surface of some cells including human neutrophils. The identification and characterization of physiologic substrates of ectoprotein kinase activity should aid the understanding of the role of this enzyme activity in cell function. Immunoprecipitation and subsequent gel electrophoresis of proteins from neutrophils labeled with [gamma-32P]ATP under conditions initially designed to detect ectoprotein kinase activity revealed that CD31, CDw32, and anti-HLA class I mAbs specifically recognize phosphoproteins on the surface of human neutrophils. Phosphorylation of these proteins was inhibited by pretreatment of cells with an impermeant sulfhydryl reagent before radiolabeling. Phosphoamino acid analysis of the proteins revealed that they contained predominantly phosphotyrosine. However, controlled proteolysis of intact cells and purified HLA class I revealed that the HLA class I heavy chain was phosphorylated on the cytoplasmic domain. These results suggest that the molecules recognized by CD31 (PECAM-1) and CDw32 (Fc gamma RII) Abs may also be phosphorylated on cytoplasmic domains under conditions originally designed to detect ectoprotein kinase activity. Phosphorylation of CD31 (PECAM-1), Fc gamma RII, and HLA class I heavy chain on tyrosine may play a role in regulating their function. These results emphasize that the demonstration that a membrane protein is an ectokinase substrate is complex and requires the definitive localization of the phosphorylated residue to the extracellular domain of the protein.

4-Chloromercuribenzenesulfonate↗
PubMed1993

Ambulatory continuous infusion ifosfamide with oral etoposide in advanced sarcomas.

BACKGROUND: Chemotherapy given by continuous infusion may have different toxicity profiles and different degrees of therapeutic efficacy than when given by bolus administration. The potential therapeutic benefits of continuous infusion chemotherapy and the advantages of outpatient treatment led us to study a continuous infusion of ifosfamide with mesna and oral etoposide. METHODS: The authors performed a Phase I-II trial in which 9 g/m2 ifosfamide was administered for 6 days and 10.5 g/m2 mesna was administered for 7 days, both by continuous infusion, in combination with 50 mg/m2/d oral etoposide for 8 days in 21 patients with sarcomas or other solid tumors. Courses were repeated every 28 days. RESULTS: A total of 65 treatment cycles were given. Only six patients required hospitalization for treatment, all because of an initial poor performance status, and most carried out normal activities on an ambulatory basis. Treatment was stopped during the first course in five patients because of central nervous system toxicity, each with a poor pretreatment performance status; neurologic recovery was complete in each patient. The dose of etoposide was decreased by 20% in 11 patients and unchanged in 7 following the first treatment. Hematologic toxicity was predominantly manifested by leukopenia. An absolute neutrophil count less than 500 neutrophils/microliters occurred in 22 of 50 cycles; thrombocytopenia (platelets less than 100,000/microliters) was seen in two patients, requiring platelet transfusion in one. Neutropenic fevers occurred in 13 of 65 cycles; in 4 of these, cultures demonstrated a bacterial infection. Nausea and vomiting were mild. Objective responses occurred in 6 of 16 patients with soft tissue sarcomas (6 partial responses [PR]) (95% confidence interval, 15-65%), and 3 of 5 bone sarcomas, all of whom had been previously treated with doxorubicin and dacarbazine. CONCLUSIONS: The authors concluded that ifosfamide and mesna given by ambulatory continuous intravenous infusion with wearable pump systems in combination with oral etoposide was well tolerated and showed substantial anti-tumor activity. This combination represents a rational therapeutic approach to patients with advanced soft tissue sarcomas and may have application to other malignancies.

Administration, Oral↗
PubMed1993

Antiserum to carcinoembryonic antigen recognizes a phosphotyrosine-containing protein in human colon cancer cell lines.

Members of the carcinoembryonic antigen (CEA) family include CEA, non-specific cross reacting antigen (NCA), and biliary glycoprotein (BGP), and appear to function as cell adhesion molecules. Immunoprecipitation and subsequent gel electrophoresis of proteins from several colon cancer cell lines labeled with [gamma-32P]ATP, under conditions designed to detect ecto-kinase-catalyzed phosphorylation of cellular proteins, revealed that polyclonal anti-CEA antiserum recognized a 175-190 kDa phosphoprotein on the surface of colon cancer cells. The ability to detect this phosphoprotein did not correlate with CEA production, and immunoprecipitation studies suggested that the phosphoprotein is BGP. Phosphoamino acid analysis of the 175-190 kDa protein showed that it contained predominantly phosphotyrosine.

Carcinoembryonic Antigen↗
PubMed1992

Activation of human phagocytes through carbohydrate antigens (CD15, sialyl-CD15, CDw17, and CDw65).

The leukocyte carbohydrate (CHO) Ag CD15, sialyl-CD15, and CDw65 have recently been found to function as ligands for CD62 and ELAM-1 cell adhesion molecules on platelets and endothelium, respectively. Cell adhesion ligands also may act as receptors capable of signal transduction. We therefore investigated the possibility that these CHO Ag and CDw17, a glycolipid Ag whose expression is regulated by leukocyte activation, may have receptor-like characteristics. The effects of antibody cross-linking of CHO Ag on phagocyte activation were measured by using flow cytometry and fluorescent indicators for cytoplasmic calcium ions, oxidative burst, and the granule-associated proteins CD11b and CD67. Cross-linking of CD15, sialyl-CD15, CDw65, or CDw17 induced a moderate release of calcium ions into the cytoplasm of granulocytes, a strong activation of oxidative burst, and a low up-regulation of CD11b and CD67 compared to the effects of treatment with 4 microM FMLP. The results suggest a role for CHO Ag in leukocyte signal transduction and support the view that these molecules are involved in phagocyte activation.

Antibodies, Monoclonal↗
PubMed1992

CD66 monoclonal antibodies recognize a phosphotyrosine-containing protein bearing a carcinoembryonic antigen cross-reacting antigen on the surface of human neutrophils.

The CD66 Ag is a neutrophil-specific "activation Ag" in that it is detected in low density on resting cells but its surface expression is up-regulated by stimulation (with the chemotactic peptide FMLP, the calcium ionophore A23187, and 12-O-tetradeconoyl-phorbol-13-acetate). Phosphorylation is an important mechanism of regulation of protein function. Although most studies of protein phosphorylation have focused on intracellular reactions, recent studies have provided evidence for the existence of ectoprotein kinase activity on the surface of several types of cells including human neutrophils. The role of ectoprotein kinase activity in cell function is unknown and little is known about the endogenous substrates of this enzyme system. The identification and characterization of physiologic substrates of ectoprotein kinase activity should aid the understanding of the role of this enzyme activity in cell function. Immunoprecipitation and subsequent gel electrophoresis of proteins from neutrophils labeled with [gamma-32P]ATP revealed that CD66 mAb specifically recognize a approximately 180-kDa phosphoprotein on the surface of human neutrophils. This protein was one of the major endogenous substrates for human neutrophil ectoprotein kinase activity. Phosphoamino acid analysis of the 180-kDa protein revealed that it contained predominantly phosphotyrosine. Preclearing studies demonstrated that this protein was also recognized by CD15 mAb, and by polyclonal anticarcinoembryonic Ag antiserum. In addition, the CD66 mAb reacted with purified carcinoembryonic Ag, biliary glycoprotein, and "nonspecific cross-reacting Ag." Thus, the neutrophil protein recognized by CD66 mAb appears to be a approximately 180-kDa form of the classical "nonspecific cross-reacting Ag" on human neutrophils.

Antibodies, Monoclonal↗