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Biomedical subjects

M E Williams

Publications and source records attributed to M E Williams.

At least 37 records · Page 2Linked to original sources
PubMed1999

Single-agent monoclonal antibody efficacy in bulky non-Hodgkin's lymphoma: results of a phase II trial of rituximab.

PURPOSE: A phase II trial was performed to evaluate the safety and efficacy of rituximab, a chimeric anti-CD20 monoclonal antibody, in patients with bulky (> 10-cm lesion) relapsed or refractory low-grade or follicular non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS: Thirty-one patients received intravenous infusions of rituximab 375 mg/m(2) weekly for four doses. All patients had at least one prior therapy (median, three; range, one to 13) and had progressive disease at study entry. Patients were a median of 4 years from diagnosis. RESULTS: No patient had treatment discontinued because of an adverse event. No patient developed human antichimeric antibody. The overall response rate in 28 assessable patients was 43% with a median time to progression of 8.1 months (range, 4.5 to 18.6+ months) and median duration of response of 5.9 months (range, 2.8 to 12.1+ months). The average decrease in lesion size in patients who achieved a partial response was 76%, and patients with stable disease had a decrease in average lesion size of 26%. Median serum antibody concentration was higher in responders compared with nonresponders, and a negative correlation was shown between antibody concentration and tumor bulk at baseline. CONCLUSION: Rituximab single-agent outpatient therapy is safe and shows significant clinical activity in patients with bulky relapsed or refractory low-grade or follicular B-cell NHL.

Adult↗
PubMed1998

IL-10 regulates liver pathology in acute murine Schistosomiasis mansoni but is not required for immune down-modulation of chronic disease.

We have used IL-10 gene knockout mice (IL-10T) to examine the role of endogenous IL-10 in the down-modulation of hepatic granuloma formation and lymphocyte responses that occurs in chronic infection with the helminth parasite Schistosoma mansoni. Although IL-10-deficient animals showed 20 to 30% mortality between 8 and 14 wk postinfection, they displayed no alterations in their susceptibility to infection and produced similar numbers of eggs as their wild-type littermates. The IL-10T mice displayed a significant increase in hepatic granuloma size at the acute stage of infection, which was associated with increased IFN-gamma, IL-2, IL-1beta, and TNF-alpha mRNA expression in liver and elevated Th1-type cytokine production by lymphoid cells. Despite developing an enhanced Th1-type cytokine response, the IL-10T mice showed no consistent decrease in their Th2-type cytokine profile. Surprisingly, although granulomatous inflammation was enhanced at the acute stage of infection, the livers of IL-10T mice displayed no significant increase in fibrosis and underwent normal immune down-modulation at the chronic stage of infection. Moreover, the down-modulated state could be induced in IL-10T mice by sensitizing the animals to schistosome eggs before infection, further demonstrating that the major down-regulatory mechanism is not dependent upon IL-10. We conclude that while IL-10 plays an important role in controlling acute granulomatous inflammation, it plays no essential role in the process of immune down-modulation in chronic schistosome infection.

Acute Disease↗
PubMed1998

Failure of P strain mice to respond to vaccination against schistosomiasis correlates with impaired production of IL-12 and up-regulation of Th2 cytokines that inhibit macrophage activation.

In contrast to most inbred strains, P mice fail to develop significant resistance to Schistosoma mansoni infection as a result of vaccination with either radiation-attenuated cercariae or schistosome antigens plus Bacillus Calmette Guérin, and this failure correlates with defects in macrophage larvicidal activity. Supernatant fluids from antigen-treated in vitro cultures of splenocytes from vaccinated P mice demonstrate less macrophage stimulatory activity than do supernatants from cells of vaccine-responsive strains such as C57BL/6. This is not due either to diminished production of the macrophage-activating cytokine IFN-gamma by P mice, or to a lesser responsiveness of macrophages from P mice to activation by IFN-gamma. Rather, P splenocytes produce two-to threefold higher amounts of IL-4 and IL-10, cytokines which down-regulate the cytotoxic potential of IFN-gamma-treated macrophages. Thus, the macrophage-activating potential of cytokine preparations from vaccinated P mice can be completely recovered by in vitro treatment with antibodies to IL-4 or IL-10. Moreover, lower levels of IL-12, a cytokine involved in promoting development of Th1 responses, are produced by splenocytes from P mice as compared to C57BL/6 counterparts. These studies indicate that a genetic predisposition toward an impaired production of IL-12 and an increased production of down-regulatory Th2 cytokines correlate with low response to vaccination against S. mansoni.

Animals↗
PubMed1998

Renal failure resulting from infiltration by inflammatory myofibroblastic tumor responsive to corticosteroid therapy.

Inflammatory myofibroblastic tumor (IMT) is a rare disease of inflammatory and spindle cell proliferative lesions in multiple sites. Most frequently reported in the lungs, a variety of extrapulmonary sites have been described. We report the first case of IMT causing renal failure by massive bilateral renal infiltration. Renal function continued to deteriorate (peak serum creatinine level, 8.4 mg/dL) despite placement of a ureteral stent. The kidneys were diffusely enlarged on computed tomographic (CT) scan. Renal biopsy showed myofibroblastic proliferation and inflammatory infiltration. Renal failure responded favorably over weeks to corticosteroid therapy (serum creatinine level, 2.8 mg/dL) with a marked reduction in bilateral renal enlargement by CT scan.

Acute Kidney Injury↗
PubMed1998

Venous thoracic outlet syndrome simulating subclavian stenosis in a hemodialysis patient.

Hemodialysis-associated subclavian venous stenosis should be suspected when upper extremity edema occurs after a graft or fistula has been placed there. Alternatively, venous thoracic outlet syndrome could also produce venous congestion, simulating subclavian stenosis. The latter diagnosis was unsuspected until central subclavian vein obstruction on venography became complete, with the arm passively hyperabducted. The patient's symptoms resolved after surgical decompression. Causes of thoracic outlet obstruction are reviewed.

Arteriovenous Shunt, Surgical↗
PubMed1998

Rituximab chimeric anti-CD20 monoclonal antibody therapy for relapsed indolent lymphoma: half of patients respond to a four-dose treatment program.

PURPOSE: The CD20 antigen is expressed on more than 90% of B-cell lymphomas. It is appealing for targeted therapy, because it does not shed or modulate. A chimeric monoclonal antibody more effectively mediates host effector functions and is itself less immunogenic than are murine antibodies. PATIENTS AND METHODS: This was a multiinstitutional trial of the chimeric anti-CD20 antibody, IDEC-C2B8. Patients with relapsed low grade or follicular lymphoma received an outpatient treatment course of IDEC-C2B8 375 mg/m2 intravenously weekly for four doses. RESULTS: From 31 centers, 166 patients were entered. Of this intent-to-treat group, 48% responded. With a median follow-up duration of 11.8 months, the projected median time to progression for responders is 13.0 months. Serum antibody levels were sustained longer after the fourth infusion than after the first, and were higher in responders and in patients with lower tumor burden. The majority of adverse events occurred during the first infusion and were grade 1 or 2; fever and chills were the most common events. Only 12% of patients had grade 3 and 3% grade 4 toxicities. A human antichimeric antibody was detected in only one patient. CONCLUSION: The response rate of 48% with IDEC-C2B8 is comparable to results with single-agent cytotoxic chemotherapy. Toxicity was mild. Attention needs to be paid to the rate of antibody infusion, with titration according to toxicity. Further investigation of this agent is warranted, including its use in conjunction with standard chemotherapy.

Adult↗
PubMed1997

Assignment of human genes for beta 2 and beta 4 subunits of voltage-dependent Ca2+ channels to chromosomes 10p12 and 2q22-q23.

We have used human beta 2 and beta 4 cDNA probes to map the genes encoding two isoforms of the regulatory beta subunit of voltage-activated Ca2+ channels, viz. CACNB2 (beta 2) and CACNB4 (beta 4), to human chromosomes 10p12 and 2q22-q23, respectively, by fluorescence in situ hybridization. The gene encoding the beta 2 protein, first described as a Lambert-Eaton myasthenic syndrome (LEMS) antigen in humans, is found close to a region that undergoes chromosome rearrangements in small cell lung cancer, which occurs in association with LEMS. CACNB2 (beta 2) and CACNB4 (beta 4) genes are members of the ion-channel gene superfamily and it should now be possible to examine their loci by linkage analysis of ion-channel-related disorders. To date, no such disease-related gene has been assigned to 10p12 and 2q22-q23.

Calcium Channels↗
PubMed1997

Late renal allograft failure secondary to thrombotic microangiopathy associated with disseminated malignancy.

A renal transplant recipient with a remote history of end-stage renal disease due to postpartum hemolytic-uremic syndrome (HUS) presented with acute renal failure after having stable renal allograft function for 9 years. A diagnosis of thrombotic microangiopathy was made based on clinical and histologic findings at renal biopsy. She was treated conservatively, never regaining graft function and ultimately succumbing from her overwhelming tumor load approximately 6 months following diagnosis of her malignancy. To our knowledge, this is the first report of thrombotic microangiopathy associated with disseminated malignancy resulting in renal allograft failure.

Acute Kidney Injury↗
PubMed1997

Reliability of a modified medication appropriateness index in ambulatory older persons.

OBJECTIVE: To evaluate the reliability of a medication appropriateness index (MAI) modified for elderly outpatients in a non-Veterans Affairs setting. DESIGN: Reliability study. SETTING: General community. PARTICIPANTS: Ten community-dwelling elderly (> 65 y) taking five or more regularly scheduled medications and participating in a university-based health service intervention study. MAIN OUTCOME MEASURES: Interrater reliability of MAI ratings of 65 medications made by two clinical pharmacists for individual items and for an overall summed score was calculated by use of kappa statistics and intraclass correlation coefficient. RESULTS: The interrater agreement for each of the individual MAI items was high for both appropriate and inappropriate ratings and ranged from 80% to 100% (overall kappa = 0.64). Overall agreement for the summed score was good (intraclass correlation = 0.80). CONCLUSIONS: The modified MAI is a reliable instrument for evaluation of medication appropriateness in a non-Veterans Affairs, ambulatory, elderly population and may provide pharmacists with a practical and standard method to evaluate patients' drug regimens and identify some potential drug-related problems.

Aged↗
PubMed1997

Shear rate dependency of red cell sequestration in skin capillaries in sickle cell disease and its variation with vasoocclusive crisis.

OBJECTIVE: To develop techniques for assessing the sequestration of red blood cells (RBCs) in skin capillaries of sickle cell disease (SCD) patients due to RBC adhesion to endothelium (EC) and RBC aggregation, and to determine the extent to which these processes correlate with onset of painful vasoocclusive crisis. METHODS: Video recordings of nailfold capillaries in the skin of patients with SCD were made during steady-state periods and episodes of painful crisis. A transient low-flow state was induced with a pressure cuff and reductions in RBC velocity were measured by spatial cross-correlation of light intensity along arterial and venous capillary limbs. An RBC accumulation index (AI) was calculated from RBC flow to represent the percentage of arterial in-flow sequestered in a capillary. An index of hematocrit (HI) was derived from axial distributions of light intensity, and a sequestration index (SI) was calculated to represent the relative increase of venous limb HI relative to that in the arterial limb with onset of stasis. RESULTS: Both AI and SI increased dramatically from zero at steady flow to a maximum as shear rates within the capillary were reduced to zero. The increase was small until shear rates (gamma) fell below a transition value (gamma T), following which both AI and SI increased sharply with onset of stasis. For 20 < or = gamma < gamma T the transient increase in AI was significantly elevated in the order AICRISIS > AISTEADY STATE > AICONTROL, thus reflecting increasing RBC sequestration in the venous limb due to either adhesion or aggregation. Compaction of RBCs in the venous limb was evidenced by increased SI that was greater than control for both steady-state and crisis subjects, but insignificantly elevated during crisis compared to steady state, thus supporting a lesser role of RBC aggregation. CONCLUSIONS: Transient sequestration of sickle RBCs in the low-flow state appears to be dominated by RBC-EC adhesion, which becomes enhanced during crisis. Although aggregation may enhance adhesive contact of RBCs with EC, it does not increase to the same extent as the rate of sequestration, thus reflecting a greater role of RBC-EC adhesion.

Anemia, Sickle Cell↗
PubMed1997

Analysis of the cyclin-dependent kinase inhibitors p18 and p19 in mantle-cell lymphoma and chronic lymphocytic leukemia.

BACKGROUND: Mantle-cell lymphoma (MCL) is characterized by overexpression of the G1 cyclin, cyclin D1, strongly implicating this cell-cycle regulatory element in MCL pathogenesis. Recently, loss-of-function mutations in cell-cycle negative regulatory elements, including p53 point mutations and deletions of the cyclin-dependent kinase inhibitors (CDKI) p15 and p16 have been described in a subset of MCLs and have been associated with aggressive clinical course, blastic morphology, and extranodal dissemination. The objective of the present study was to analyze two newly identified members of the p16 (INK4A; MTS1) CDKI family, p18 and p19, in MCL. Such analyses have not been previously reported. PATIENTS AND METHODS: DNA was isolated from tissue biopsies, peripheral blood cells, or bone marrow cells of 45 patients with MCL and 15 with chronic lymphocytic leukemia (CLL). Southern blot analysis was performed with p18 and p19 probes and compared to placental control DNA and to control probe hybridizations for evidence of p18 or p19 gene deletion or rearrangement. RESULTS: P18 deletion was identified in one MCL but in no case of CLL. One MCL sample had rearrangement of the p18 gene; this case also had coexisting homozygous p15 and p16 deletion. Both cases with p18 abnormalities had blastic morphology, and one had extranodal disease with renal parenchymal invasion. CONCLUSIONS: P18 rearrangement or deletion as detected by Southern blot is a rare event in MCL, but may be associated with blastic morphology. P53 mutations and deletions of the CDKI p15 and p16 appear to be more frequent in MCL, although further studies are necessary to assess the presence of inactivating point mutations or altered expression of p16 family proteins.

Antigens, Neoplasm↗
PubMed1996

T cell-derived IL-3 induces the production of IL-4 by non-B, non-T cells to amplify the Th2-cytokine response to a non-parasite antigen in Schistosoma mansoni-infected mice.

We describe a novel amplification mechanism underlying the increased early IL-4 production observed in Schistosoma mansoni-infected mice in response to a non-parasite Ag, sperm whale myoglobin (SwMb). Earlier studies have shown that splenic Fc epsilon R+ non-B, non-T (NBNT) cells from schistosome-infected mice secrete IL-4 after stimulation with parasite Ag. We now demonstrate that purified NBNT cells from SwMb-immunized S. mansoni-infected mice do not respond directly to SwMb, but produce IL-4 in response to IL-3. Accordingly, we show that the early SwMb-specific IL-4 response of spleen cells (SC) from immunized infected mice is dependent on IL-3 and on CD4+ T cells. Thus, most of the early SwMb-induced IL-4 from SC of infected mice appears to be produced by NBNT cells triggered by IL-3 synthesized by SwMb-specific CD4+ T cells. IL-3-induced IL-4 production was also observed in purified NBNT cells from immunized uninfected mice, but the frequency and/or IL-4-producing capacity of splenic IL-3-responsive cells was found to be 8 to 16 times higher in immunized infected animals. IL-4 production by purified CD4+ cells from immunized infected mice was also seen after SwMb stimulation, but this response showed slower kinetics than those of total SC, was IL-3-independent, and on average threefold greater than that by CD4+ cells from immunized uninfected controls. Thus, increased SwMb-induced IL-4 production in immunized S. mansoni-infected mice results from direct synthesis by CD4+ T cells, as well as their stimulation via IL-3 of an expanded population of NBNT cells. The latter pathway may serve as an amplification loop for Th2-cytokine responses.

Animals↗
PubMed1996

Natural killer-like T-cell lymphomas: aggressive lymphomas of T-large granular lymphocytes.

Natural killer (NK)-like T cells are major histocompatibility complex-unrestricted cytotoxic T cells that are surface CD3-positive, express NK-cell antigens, and rearrange their T-cell receptor. Most neoplasms arising from this T-cell subpopulation have been a chronic lymphoproliferative disease referred to as T-large granular lymphocyte (LGL) leukemia. Only 10 NK-like T-cell lymphomas have been described in detail previously; this study presents the clinicopathologic features of six others and distinguishes these lymphomas from T-LGL leukemia. All patients presented with B-symptoms and often had marked hepatosplenomegaly without significant peripheral lymphadenopathy. Four of the six patients were immunosuppressed. All had CD3, CD8, CD56-positive tumors, presumably of hepatosplenic (n = 3), intestinal (n = 1), pulmonary (n = 1), or nodal (n = 1) origin. Three patients had lymphomatous bone marrow infiltrates, and four had peripheral blood involvement by neoplastic large lymphocytes, some of which had a blastic appearance or resembled virocytes. Azurophilic granules, ultrastructurally corresponding to cytoplasmic dense core and/or double density granules, were seen in all cases. T-cell clonality was shown in five tumors by Southern blot analysis, and three had abnormal karyotypes. Two untreated patients died 20 days after presentation, and three patients who received combination chemotherapy died within 5 months of presentation. One patient remains in complete remission 22 months after treatment. These findings suggest NK-like T-cell lymphomas are aggressive, are clinicopathologically distinct from T-LGL leukemia, and should be in the differential diagnosis of extranodal T-cell lymphoproliferations, including those in immunosuppressed patients. Furthermore, the LGL morphology, phenotype, and tissue distribution of some NK-like T-cell lymphomas suggest they arise from thymic-independent T cells of the hepatic sinusoids and intestinal mucosa.

Adolescent↗
PubMed1996

The morphologic spectrum of non-Hodgkin's lymphomas with BCL1/cyclin D1 gene rearrangements.

BCL1/PRAD1 gene rearrangements involving the cyclin D1 gene are a feature of about 70% of centrocytic/mantle-cell lymphomas (CC/MCL) but are identified in only a small proportion of other B-cell non-Hodgkin's lymphomas. Of 37 lymphomas found to have BCL1/cyclin D1 (PRAD1, CCND1) gene rearrangements, 30 fit the morphologic and immunophenotypic criteria for typical CC/MCL. Seven cases with morphologic features atypical for CC/MCL were identified. CD5+ monoclonal B cells were documented in all these cases. Six cases were subsequently stained for cyclin D1 protein, and all showed nuclear positivity. Five cases had variably sized foci of cells with moderately abundant pale cytoplasm resembling parafollicular/monocytoid B cells, marginal zone cells, hairy cells, or even proliferation centers. Transformed-appearing cells were also present in some lymphomas. In one case, striking follicular colonization created a markedly nodular growth pattern mimicking a follicular lymphoma. A sixth case had a marked predominance of small, round lymphocytes at some sites, mimicking a small lymphocytic lymphoma. Five of these six cases also had areas more typical of CC/MCL. The seventh case was a CD5-positive splenic marginal zone-like lymphoma (SMZL) with plasmacytic differentiation and circulating villous lymphocytes consistent with a splenic lymphoma with villous lymphocytes (SLVL). These cases illustrate the morphologic spectrum of small B-cell lymphoid neoplasms that have BCL1/cyclin D1 gene rearrangements and overexpression of cyclin D1. Despite the BCL1 translocation and cyclin D1 overexpression, the splenic lymphoma with plasmacytic differentiation was definitely not a CC/MCL and fit the clinicopathologic entity of SMZL/SLVL. The other six cases are best considered CC/MCL variants based on a combined morphologic, immunophenotypic, and genotypic evaluation. Genotypic or immunophenotypic studies to identify cyclin D1 rearrangements and overexpression, although not pathognomonic, are useful in recognizing these variant CC/MCL cases, which can mimic almost any of the other well-described but more indolent low-grade B-cell lymphomas and leukemias. Some of the variant CC/MCL cases had features in common with the CD5+ cyclin D1+ SMZL/SLVL, suggesting a possible relationship between these two otherwise distinct entities.

Adult↗
PubMed1996

Incremental value of myocardial perfusion scintigraphy in prognosis and outcomes of patients with coronary artery disease.

The concept of incremental value in prognosis and outcome of patients with coronary artery disease is important to the field of noninvasive imaging. Because these tests are expensive, they should be held to the standard of demonstrating a statistical improvement over the information provided by clinical assessment and treadmill testing. Responding to the demand for cost-effective applications of myocardial perfusion scintigraphy, a large amount of research has recently been devoted to defining specific patient subsets in which incremental value exists for scintigraphy. Subsets thus far demonstrated to benefit incrementally include those men and women referred for possible coronary artery disease, with known coronary artery disease, and after percutaneous transluminal coronary angioplasty, coronary artery bypass grafting, unstable angina, or recent infarction. Incremental cost savings also apply to these subsets except for patients with normal ECGs at rest and less than 15% likelihood for significant coronary artery disease.

Angioplasty, Balloon, Coronary↗