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Biomedical subjects

M J Robertson

Publications and source records attributed to M J Robertson.

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

Autologous transplantation of mobilized peripheral blood CD34+ cells selected by immunomagnetic procedures in patients with multiple myeloma.

In the use of autologous PBPC transplantation in patients with multiple myeloma, contamination of PBPC with myeloma cells is commonly observed. Enrichment for CD34+ cells has been employed as a method of reducing this contamination. In this study the reduction of myeloma cells in PBPC was accomplished by the positive selection of CD34+ cells using immunomagnetic bead separation (Isolex 300 system). PBPC were mobilized from 18 patients using cyclophosphamide (4.5 g/m2) and G-CSF (10 microg/kg/day). A median of two leukaphereses and one selection was performed per patient. The median number of mononuclear cells processed was 3.50 x 10(10) with a recovery of 1.11 x 10(8) cells after selection. The median recovery of CD34+ cells was 48% (range 17-78) and purity was 90% (29-99). The median log depletion of CD19+ cells was 3.0. IgH rearrangement, assessed by PCR, was undetectable in 13 of 24 evaluable CD34+ enriched products. Patients received 200 mg/m2 of melphalan followed by the infusion of a median of 2.91 x 10(6)/kg CD34+ cells (1.00-16.30). The median time to absolute neutrophil count >0.5 x 10(9)/l was 11 days, and sustained platelet recovery of >20 x 10(9)/l was 14 days. We conclude that immunomagnetic-based enrichment of CD34+ cells results in a marked reduction in myeloma cells without affecting engraftment kinetics.

Adult↗
PubMed1998

A longitudinal perspective on entitlement income among homeless adults.

OBJECTIVE: Sources of entitlement income were examined in a sample of homeless adults to determine whether certain subgroups more consistently obtain entitlement income and are more likely to continue receiving it over time. METHODS: From a baseline sample of 564 homeless residents of Alameda County, California, 397 were interviewed at both five- and 15-month follow-ups. Information was obtained on income received from public sources in the 30 days before each interview, including general assistance, Aid to Families With Dependent Children (AFDC), Supplemental Security Income, or Social Security Disability Insurance. Data were also obtained on psychiatric diagnosis, race, marital status, education, duration of homelessness in adulthood, household status, and reported disability. RESULTS: At baseline fewer than half of the respondents were receiving any entitlement income. The benefits of almost half of the AFDC and general assistance recipients were terminated during the 15-month period. Respondents who continued receiving entitlement income over the 15-month period were more likely to be black, to be women alone or with children, to have a family history of receiving welfare, and to report a disability. Respondents with dual disorders were six times more likely than others to have their benefits terminated. CONCLUSIONS: Entitlement income is tenuous for many homeless adults, particularly those with dual diagnoses.

Adult↗
PubMed1998

Cancer screening in homeless women: attitudes and behaviors.

Little is known about the use of cancer-screening services in homeless women and their attitudes about early detection programs. Face-to-face interviews were conducted with homeless women in San Francisco to determine rates of clinical breast exams, mammograms, and Pap smears. A total of 105 women were randomly selected from two homeless shelters. By self-report, 51 percent were current on clinical breast exams, 47 percent on mammograms, and 54 percent on Pap smears. These women had very positive attitudes toward receiving cancer-screening exams. In multivariate analyses, discussion about cancer prevention with a health care provider predicted current clinical breast exams and mammograms. More medical visits predicted being current on mammograms and Pap smears. Although homeless women represent a unique group of the urban poor, they are accessing cancer-screening exams at rates comparable to the general population.

Adult↗
PubMed1997

CD94 ligation induces apoptosis in a subset of IL-2-stimulated NK cells.

CD94 (Kp43) is a member of the human C-type lectin superfamily encoding type II membrane glycoproteins expressed on NK cells and a subset of T cells. Ligation of CD94 has been shown to either potentiate or inhibit NK cell proliferation and cytolytic effector function. Here we show that CD94 ligation triggers apoptosis in IL-2-primed NK cells. Evidence for CD94-induced apoptosis includes: 1) chromatin condensation as measured by increased fluorescence of Hoechst dye, 2) induction of DNA fragmentation, and 3) characteristic morphology by transmission electron microscopy. IL-2 priming (at least 12 h) is required for activation-induced NK cell death triggered by CD94. Activation-induced NK cell death triggered by CD94 ligation is extremely rapid (DNA fragmentation is first observed at 120 min). Unlike activation-induced T cell death, it is not inhibited by neutralizing Abs reactive with TNF-alpha or Fas ligand. Our results suggest that CD94 may play a role in the elimination of activated NK cells during the transition from the innate to the Ag-specific immune response.

Antibodies, Monoclonal↗
PubMed1997

Activation of T-cells through an antigen-independent alternative pathway induces precocious sensitivity to Fas-induced apoptosis.

Autoreactive T-cells can be activated inadvertently during immune responses through antigen-independent pathways. It has been suggested that Fas/Fas ligand interactions may play a role in eliminating these cells, but the extent that cells activated through such alternative pathways are sensitive to Fas-induced apoptosis has not been extensively evaluated. Proliferation of peripheral blood T-cells from normal individuals activated for 4 days with PHA or PMA + ionophore was not influenced by the presence of anti-Fas antibody. When the same cells were activated with soluble factors produced by previously activated T-cells (lymphostimulatory activity), anti-Fas antibodies inhibited thymidine incorporation by 74+/-4%. The presence of typical morphological changes and oligonucleosomal fragmentation of DNA indicated that the reduced proliferation resulted from apoptotic death of the lymphoblasts. Fas-sensitivity of T-cells activated by lymphostimulatory activity was first detectable 4 days after activation, and at 5 days the majority of lymphoblasts had become sensitive to Fas, whereas no evidence of sensitivity to Fas was observed for lymphoblasts generated by PHA or PMA + ionophore during the first 5 days of culture. Incubation of cells activated with PHA or PMA+ ionophore in the presence of IL-2 at concentrations 10-fold higher than that present in lymphostimulatory activity did not induce early sensitivity to Fas, indicating that exposure to IL-2 could not explain the precocious development of sensitivity to Fas seen following activation by lymphostimulatory activity. These studies demonstrate that T-cells activated through an antigen-independent 'alternative' pathway develop precocious sensitivity to Fas-induced apoptosis, which may be important in permitting the elimination of autoreactive bystander cells activated in the course of immune responses.

Adult↗
PubMed1997

Differential role of tyrosine phosphorylation in the induction of apoptosis in T cell clones via CD95 or the TCR/CD3-complex.

Activated T cells undergo apoptosis when the Fas-antigen (APO-1, CD95) is ligated by Fas Ligand (FasL) or agonistic anti-Fas antibodies. Repeated stimulation of T lymphocytes via the TCR/CD3-complex induces activation-induced cell death (AICD) associated with FasL surface expression. FasL binding to Fas molecules triggers the Fas-dependent death signaling cascade. Since it is still controversial whether Fas-induced cell death is associated with tyrosine kinase activity, we investigated the tyrosine kinase activation requirements in anti-Fas antibody-induced cell death and AICD in human T cell clones. We report that cell death triggered by anti-Fas antibody is not accompanied by an increase in tyrosine phosphorylation and cannot be blocked by inhibitors of protein tyrosine kinases (PTK). Under the same conditions, AICD of T cell clones is clearly associated with tyrosine kinase activation. In fact, semiquantitative RT-PCR analysis of FasL mRNA expression triggered in T cell clones via the TCR/CD3-complex revealed that tyrosine phosphorylation is required for functional FasL mRNA and surface expression.

Journal Article↗
PubMed1997

Role of the CD40 and CD95 (APO-1/Fas) antigens in the apoptosis of human B-cell malignancies.

Ligation of CD40 inhibits apoptosis and stimulates proliferation of normal B cells, whereas ligation of CD95 (APO-1/Fas) induces apoptosis of activated lymphocytes. Aberrant signalling through the CD40 and CD95 antigens could thus participate in the pathogenesis of lymphoid malignancies. The expression and function of CD40 and CD95 on neoplastic B cells from patients with acute lymphoblastic leukaemia (ALL), chronic lymphocytic leukaemia (CLL) and non-Hodgkin's lymphoma (NHL) were examined. CD40 was expressed by all 30 B-cell tumours, whereas CD95 was detected on neoplastic B cells in only one of 10 cases of ALL, two of 10 cases of CLL, and three of 10 cases of NHL. Incubation with an agonistic CD95 monoclonal antibody (MoAb) did not augment apoptosis in any of the unstimulated B-cell neoplasms. CD40 triggering did not consistently inhibit spontaneous apoptosis, but ultimately stimulated the growth of neoplastic B cells in most cases. Furthermore, CD40 activation led to up-regulation of the CD95 antigen in all 30 B-cell neoplasms. Ligation of CD95 on CD40-activated tumour cells augmented apoptosis in five of 10 ALL, three of 10 CLL, and nine of 10 NHL cases. The degree of apoptosis induced by CD95 triggering was greater for NHL cells than for ALL cells or CLL cells. Bcl-2 expression by ALL and NHL cells was substantially decreased after in vitro culture, whereas Bcl-2 expression by CLL cells was not significantly changed. However, there was no correlation between the level of Bcl-2 expression and sensitivity to CD95-mediated apoptosis. Thus, factors other than levels of CD95 and Bcl-2 determine susceptibility of malignant B cells to apoptosis after CD95 triggering. CD40-activated lymphoma cells appear to be very sensitive to CD95-mediated apoptosis, suggesting potential strategies for treatment of NHL. Elucidation of the mechanisms underlying resistance of ALL and CLL cells to CD95 triggering may facilitate the development of novel therapeutic approaches to these diseases as well.

Apoptosis↗
PubMed1997

Drug use disorders and treatment contact among homeless adults in Alameda County, California.

OBJECTIVES: This study estimates the extent and distribution of specific drug problems among homeless adults. METHODS: A countywide probability sample of 564 homeless adults received structured interviews that included a standardized assessment of substance use disorders. RESULTS: Two thirds of the sample (69.1%) had a lifetime history of a substance use disorder (including abuse of or dependence on alcohol [52.6%] or drugs [52.2%]); half had a current (52.4%) substance use disorder (including alcohol [38.8%] or drugs [31.3%]). Current drug disorders were higher among respondents who were younger, homeless longer, or sampled from the city of Oakland, Calif. Alcohol use disorders were higher among men than among women; surprisingly, drug use disorders were not. CONCLUSION: Rates of current drug use disorders for homeless adults were more than eight times higher than general population estimates. However, estimates of drug problems among homeless adults vary as a function of case ascertainment and sampling strategy. Estimates based only on samples from urban areas may overestimate drug problems among the area's larger homeless populations.

Adolescent↗
PubMed1997

Phase I evaluation of intravenous recombinant human interleukin 12 in patients with advanced malignancies.

A Phase I dose escalation trial of i.v. administered recombinant human interleukin 12 (rhIL-12) was performed to determine its toxicity, maximum tolerated dose (MTD), pharmacokinetics, and biological and potential antineoplastic effects. Cohorts of four to six patients with advanced cancer, Karnofsky performance >/=70%, and normal organ function received escalating doses (3-1000 ng/kg/day) of rhIL-12 (Genetics Institute, Inc.) by bolus i.v. injection once as an inpatient and then, after a 2-week rest period, once daily for five days every 3 weeks as an outpatient. Therapy was withheld for grade 3 toxicity (grade 4 hyperbilirubinemia or neutropenia), and dose escalation was halted if three of six patients experienced a dose-limiting toxicity (DLT). After establishment of the MTD, eight more patients were enrolled to further assess the safety, pharmacokinetics, and immunobiology of this dose. Forty patients were enrolled, including 20 with renal cancer, 12 with melanoma, and 5 with colon cancer; 25 patients had received prior systemic therapy. Common toxicities included fever/chills, fatigue, nausea, vomiting, and headache. Fever was first observed at the 3 ng/kg dose level, typically occurred 8-12 h after rhIL-12 administration, and was incompletely suppressed with nonsteroidal anti-inflammatory drugs. Routine laboratory changes included anemia, neutropenia, lymphopenia, hyperglycemia, thrombocytopenia, and hypoalbuminemia. DLTs included oral stomatitis and liver function test abnormalities, predominantly elevated transaminases, which occurred in three of four patients at the 1000 ng/kg dose level. The 500 ng/kg dose level was determined to be the MTD. This dose, administered by this schedule, was associated with asymptomatic hepatic function test abnormalities in three patients and an onstudy death due to Clostridia perfringens septicemia but was otherwise well tolerated by the 14 patients treated in the dose escalation and safety phases. The T1/2 elimination of rhIL-12 was calculated to be 5.3-9.6 h. Biological effects included dose-dependent increases in circulating IFN-gamma, which exhibited attenuation with subsequent cycles. Serum neopterin rose in a reproducible fashion regardless of dose or cycle. Tumor necrosis factor alpha was not detected by ELISA. One of 40 patients developed a low titer antibody to rhIL-12. Lymphopenia was observed at all dose levels, with recovery occurring within several days of completing treatment without rebound lymphocytosis. There was one partial response (renal cell cancer) and one transient complete response (melanoma), both in previously untreated patients. Four additional patients received all proposed treatment without disease progression. rhIL-12 administered according to this schedule is biologically and clinically active at doses tolerable by most patients in an outpatient setting. Nonetheless, additional Phase I studies examining different schedules and the mechanisms of the specific DLTs are indicated before proceeding to Phase II testing.

Adult↗
PubMed1996

Rapid modulation of T lymphocyte surface antigens induced by Fas (CD95, APO-1) ligation.

Crosslinking the Fas (CD95, APO-1) antigen by mAb or Fas-ligand (Fas-L)-expressing cells triggers apoptosis. We have investigated the early consequences of Fas signaling on the expression of various cell surface antigens on T lymphocytes. Incubation of Fas-sensitive Jurkat (JM) cells with agonistic anti-Fas mAb induced rapid (within 4 hr) downmodulation of L-selectin (CD62L) and CD7 but not of CD3 or CD71. No modulation was observed on Fas-expressing but Fas-resistant JM variant 432.1. On PHA-activated, Fas-sensitive T cell blasts, anti-Fas mAb rapidly triggered downmodulation of a variety of antigens, including CD2, CD4, CD8, CD7, CD44, LFA1alpha, LFA1beta, and CD62L, but not CD3, CD25, or CD26. Most of these antigens were not downmodulated by either CD3 crosslinking (except CD3) or PMA treatment (except CD3, CD4, and CD62L). Comparable patterns of biphasic CD44, LFA1alpha, and LFA1beta expression were observed on CD4+ and CD8+ T cell blasts in response to Fas crosslinking. In these instances, downregulation occurred preferentially on cells undergoing rapid shrinkage. These results indicate that rapid downregulation of selected surface antigens is an early response of both normal and transformed T cells to Fas crosslinking.

Antigens, CD↗
PubMed1996

High-dose therapy and autologous bone marrow transplantation in patients with follicular lymphoma during first remission.

We report the results of a study in previously untreated advanced stage patients with follicular lymphoma (FL) who underwent uniform induction chemotherapy with cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP) followed by myeloablative therapy and anti-B-cell monoclonal antibody purged autologous bone marrow transplantation (ABMT). Eighty-three patients with previously untreated, low-grade FL were enrolled. After CHOP induction, only 36% achieved complete remission (CR) and 77 patients underwent ABMT. Before BM harvest, 70 patients had a known t(14;18), as determined by polymerase chain reaction (PCR), and all remained PCR positive in the BM at harvest. After ABMT, the disease-free survival (DFS) and overall survival are estimated to be 63% and 89% at 3 years, respectively, with a median follow-up of 45 months. Patients whose BM was PCR negative after purging experienced significantly longer freedom from recurrence (FFR) than those whose BM remained PCR positive (P = .0006). Continued PCR negativity in follow-up BM samples was also strongly predictive of continued CR. This study suggests that a subset of patients with advanced FL may experience prolonged clinical and molecular remissions following high-dose ablative therapy, although longer follow-up will be necessary to determine potential impact on overall survival.

Adult↗
PubMed1996

Induction of cell death via Fas (CD95, Apo-1) may be associated with but is not dependent on Fas-induced tyrosine phosphorylation.

Cross-linking of the Fas-antigen (CD95, Apo-1) triggers apoptosis in activated T cells and transformed T cell lines. Fas-induced apoptosis has been previously reported to require Fas-triggered tyrosine phosphorylation of various proteins. In the present study, we have compared the protein tyrosine phosphorylation pattern and the apoptosis sensitivity in a set of Jurkat variants selected for the absence or presence of T cell receptor (TCR)/CD3 expression and resistance or sensitivity to Fas-mediated apoptosis. While tyrosine phosphorylation upon Fas-ligation was readily apparent in wild-type Jurkat cells (which are sensitive to anti-Fas-induced apoptosis), drastically reduced tyrosine phosphorylation was observed in Fas-resistant Jurkat subclones (which still express CD95 on their surface). More importantly, TCR/CD3-negative Jurkat variants which expressed normal levels of CD95 and were fully susceptible to Fas-triggered cell death, did not show any protein tyrosine phosphorylation upon Fas-ligation. Taken together, our data demonstrate that Fas-induced cell death can be associated with but is not dependent on protein tyrosine phosphorylation.

Antibodies, Monoclonal↗
PubMed1996

Mental health problems of homeless women and differences across subgroups.

Homeless women are a large and diverse group, constituting one fifth of the US homeless adult population. Although most homeless women do not have major mental illness, homeless women exhibit disproportionately high rates of major mental disorders and other mental problems. Rates of mental disorders are highest among whites and women without children, and important variations by subgroups of homeless women reinforce the need for disaggregated analysis. Many homeless women with serious mental illness are not receiving needed care, apparently due in part to the lack of perception of a mental health problem and the lack of services designed to meet the special needs of homeless women.

Adult↗
PubMed1996

Sources of income among homeless adults with major mental disorders or substance use disorders.

OBJECTIVE: The study documented sources and amounts of income among homeless adults with major mental or substance use disorders. It examined whether income varied by diagnostic group and whether those who received case management would be more likely to have income. METHODS: A total of 564 homeless adults from a countywide probability sample completed structured interviews. Based on DSM-III-R criteria, respondents were divided into four groups--those with current major mental disorders, substance use disorders, dual disorders, and no disorders. Income from entitlement benefits, formalsector employment, informal-sector employment, and other sources was documented by group. Logistic regression analysis was used to examine relationships between income sources, case management, and diagnostic groups. RESULTS: Although informal-sector income was the most common income source, it provided the fewest median dollars per month ($42). Entitlement benefits provided the most monthly income ($340) and was the second most common source. Respondents with major mental disorders, substance use disorders, or dual disorders were no less likely than those with no disorders to report income from entitlement benefits or formal-sector employment. Among those with major mental disorders, substance use disorders, or dual disorders, respondents who had recent case management were four to nine times more likely to report entitlement income. CONCLUSIONS: The results support other research and anecdotal findings on the importance of case management in obtaining entitlement income among homeless adults with major mental or substance use disorders.

Adolescent↗
PubMed1996

Characterization of a cell line, NKL, derived from an aggressive human natural killer cell leukemia.

Cell line NKL was established from the the peripheral blood of a patient with CD3-CD16+CD56+ large granular lymphocyte (LGL) leukemia. The neoplastic LGL of this patient mediated natural killing and antibody-dependent cellular cytotoxicity (ADCC) and exhibited proliferative responses similar to normal CD16+CD56dim natural killer (NK) cells. The Morphology of NKL cells resembles that of normal activated NK cells. The karyotype of NKL is 47, XY, add (1) (q42), +6 del (6) (q15 q23), del (17) (p11). NKL cells express CD2, CD6, CD11a, CD26, CD27, CD29, CD38, CD43, CD58, CD81, CD94, CD95, class II MHC, and the C1.7.1 antigen, but do not express detectable levels of CD3, CD4, CD5, CD8, CD14, CD19, CD20, CD28, alpha/beta or gamma/delta T cell receptors on the cell surface. The density of the CD16, CD56, and CD57 antigens declined markedly on NKL cells during prolonged im vitro culture. Nevertheless, NKL cells can mediate ADCC as well as natural killing. NKL cells are strictly dependent on interleukin-2 (IL-2) for sustained growth and die if deprived of IL-2 for more than 7 days. NKL cells proliferate in response to concentrations of IL-2 as low as 1 pM, but an optimal proliferative response requires approximately 100 pM IL-2. NKL cells growing in the presence of IL-2 express abundant IL-2R alpha with little or no detectable IL-2 beta or gamma chain on the cell surface; NKL cells deprived of IL-2 express high levels of both IL-2R alpha and beta. IL-4, IL-7, and IL-12, unlike IL-2, do not maintain the viability of NKL cells. Furthermore, IL-1, IL-4, IL-6, IL-7, IL-12, tumor necrosis factor-alpha (TNF-alpha), interferon-alpha (IFN-alpha) and IFN-gamma do not support the growth of NKL cells. The NKL cell line may prove useful for studies of human NK cell biology.

Antigens, CD↗
PubMed1996

Expression of CD95 antigen and Bcl-2 protein in non-Hodgkin's lymphomas and Hodgkin's disease.

CD95 (APO-1/Fas) is a member of the superfamily that includes the nerve growth factor and tumor necrosis factor receptors, OX40, CD27, CD30, and CD40. Present on a minority of resting blood lymphocytes, CD95 expression is upregulated on activated T and B lymphocytes and natural killer cells, where binding of the antigen by anti-Fas and anti-APO-1 antibodies has been shown to induce apoptosis. This CD95-mediated apoptosis is at least partially inhibited by expression of the Bcl-2 protooncogene. To evaluate possible roles of CD95 and Bcl-2 in growth regulation of lymphoid neoplasms, we studied by immunohistochemistry the expression of CD95 and Bcl-2 in 67 B- and 5 T-cell lymphomas, and 10 cases of Hodgkin's disease. In all, 29 B and 2 T cell lymphomas, and 9 cases of Hodgkin's disease expressed CD95. Compared with diffuse large B-cell and Burkitt-like lymphomas, lowgrade B-cell lymphomas more frequently expressed CD95 (52% versus 26%; P < .005). None of the B-cell small lymphocytic lymphomas or mantle cell lymphomas expressed CD95, whereas the majority of follicle center lymphomas, extranodal marginal zone B-cell lymphomas, and immunocytomas were CD95+. Of the 29 CD95+ B-cell lymphomas, only 33% of the high-grade group coexpressed Bcl-2, compared with 87% of the low-grade group (P < .04). Two of three peripheral T-cell lymphomas--including one anaplastic large cell lymphoma--expressed CD95. Staining for CD95 was seen in 9 of 10 cases of Hodgkin's disease. The infrequent expression of CD95 in high-grade B-cell lymphomas suggests an association between loss of CD95 expression/function and a more aggressive tumor grade. Whereas frequent coexpression of Bcl-2 with CD95 may protect low-grade B-cell lymphomas against CD95-mediated apoptosis, in the high-grade group such coexpression is infrequent, and other regulators besides Bcl-2 may be involved in modulating the apoptosis signal delivered by CD95.

Animals↗
PubMed1995

A triplet of nuclease proteins (NP42-50) is activated in human Jurkat cells undergoing apoptosis.

Activation of a triplet of nuclear proteins (NP42-50) was observed in human Jurkat T cell line following treatment with an antibody to CD95 (Fas/Apo-1), a cell surface molecule involved in apoptotic cell death. The nuclease activity, corresponding to a triplet of proteins observed at approximately 42, 45, and 50 kDa in size, was extractable, heat-stable, and detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis containing deoxyribonucleic acids (SDS-PAGE-DNA) assay. The NP42-50 activity requires the presence of Mg2+/Ca2+ and is insensitive to inactivation by heating at 80 degrees C for 5 min. Zinc effectively inhibited the enzymatic activity of NP42-50 on SDS-PAGE-DNA and also protected Jurkat cells from the CD95-mediated apoptosis in cell cultures. The nuclease activation, however, was not a unique pathway for the CD95-mediated cell death. The apoptosis induced by arabinofuranosyl cytosine, a chemotherapeutic agent, also activated the NP42-50 nuclease activity in Jurkat cells, suggesting that a similar cascade of subsequent events in apoptosis may occur in most instances although many different signals can initiate apoptotic cell death in various cell types. The nuclease identified by this study appears to be distinguishable from DNase I or DNase II by its molecular characteristics and its enzymatic requirements. The NP42-50, with respect to the nuclease activity closely associated with apoptotic cell death, may serve as a candidate for the endonuclease(s) involved in the cleavage of DNA into fragments during apoptosis.

Amino Acid Sequence↗