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Biomedical subjects

J P Greer

Publications and source records attributed to J P Greer.

At least 55 records · Page 3Linked to original sources
PubMed1992

T-cell-rich B-cell lymphomas. A clinicopathologic study of 19 cases.

T-cell-rich B-cell lymphomas (TCRBCLs) are recently described, unusual non-Hodgkin's lymphomas that have a diffuse morphology, a predominance of reactive T-cells, and a minority of neoplastic B-cells. The clinical and pathological features of 19 TCRBCLs, all of which demonstrated B-cell clonality, are presented. These lymphomas generally affected older patients by widespread disease and usually were nodal in origin. Treatment varied, but continuous complete remissions (eight patients) were achieved only in those receiving chemotherapy directed at intermediate-grade lymphomas. Although morphologically heterogeneous, all cases resembled peripheral T-cell lymphomas (PTCLs); several TCRBCLs also contained Reed-Sternberg-like cells. Flow cytometry or frozen-section immunoperoxidase failed to detect monotypic immunoglobulin (Ig) in eight of eight cases tested. In contrast, paraffin immunoperoxidase was very useful diagnostically, showing large L26 (CD20-associated) positive cells scattered singly or in small clusters among numerous small T-cells (UCHL1[CD45RO] positive) in all cases. Monotypic cytoplasmic Ig was present in 16 of 19 cases, one of which exhibited plasmacytic differentiation. Southern blot analysis demonstrated relatively faint Ig JH and/or JK bands, indicating a small monoclonal B-cell population in nine of 11 cases, one of which also showed a bcl-2 rearrangement. No T-cell receptor gene rearrangements were observed. These results showed that TCRBCLs may be easily confused with PTCLs or occasionally confused with Hodgkin's disease. TCRBCLs are probably heterogeneous biologically; some cases are of follicular center cell origin. These lymphomas respond to chemotherapy directed at intermediate-grade lymphomas, apparently have a better prognosis than PTCLs, and seem to represent morphological variants of different types of large B-cell lymphomas.

Adolescent↗
PubMed1991

Epipodophyllotoxin-related leukemia. Identification of a new subset of secondary leukemia.

Thirty-seven children and adults who developed acute nonlymphocytic leukemia after the administration of chemotherapy that included etoposide or teniposide for a variety of hematologic and solid malignancies were identified. The secondary leukemia that occurred in these patients could be distinguished from the secondary leukemia that occurs after treatment with alkylating agents by the following: a shorter latency period; a predominance of monocytic or myelomonocytic features; and frequent cytogenetic abnormalities involving 11q23. Patients receiving an epipodophyllotoxin are at risk for developing secondary leukemia that has features distinct from the syndrome of secondary leukemia associated with alkylating agents.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Results of treatment with high intensity, brief duration chemotherapy in poor prognosis non-Hodgkin's lymphoma.

A novel chemotherapeutic approach was designed for the treatment of intermediate and high-grade histology non-Hodgkin's lymphoma using augmented (but subtransplantation) doses of chemotherapy administered at frequent intervals in the inpatient setting. For the initial evaluation of this regimen, poor prognosis patients were treated with a projected long-term survival rate of less than 25% in response to standard therapy. Between March 1982 and May 1988, 56 previously untreated patients were entered into this study; all patients had either high-grade histology (20 patients) or predominantly large cell lymphoma (36 patients). Median age was 41.5 years (range, 18 to 69 years). Poor prognosis features included: Stage IV, 71%; poor performance status (Eastern Cooperative Oncology Group scale, 2 to 4), 55%; multiple extranodal sites of disease, 52%; elevated lactic dehydrogenase (greater than 300 IU/l), 43%; and bulky (greater than 10 cm) tumor masses, 30%. Thirty-three of 56 patients (59%) were in Shipp's Category 3. During the 6-year study, the chemotherapy regimen was modified in an attempt to improve efficacy and reduce toxicity. However, most patients received a 2-month course of therapy as follows: cyclophosphamide 1500 mg/m2 intravenously (IV) on days 1, 2, and 29; etoposide 400 mg/m2 IV on days 1, 2, and 3 and 100 mg/m2 on days 29, 30, 31; doxorubicin 45 mg/m2 IV on days 29, 30; vincristine 1.4 mg/m2 IV on days 8, 22, 36, and 50; bleomycin 10 units/m2 IV on days 8, 22, 36, and 50; methotrexate 200 mg/m2 IV on days 15 and 43 followed 24 hours later by leucovorin 15 mg/m2 IV every 6 hours for six doses; and prednisone 60 mg/m2 orally on days 1 to 7 and 29 to 35. The complete response (CR) rate was 77% (95% confidence interval, 64% to 86%). There were ten relapses, only one of which occurred after 18 months of follow-up. Overall event-free survival (EFS) was 52% (95% confidence interval, 36% to 68%), with a median follow-up of 36 months. Eleven of 13 patients with small noncleaved lymphoma had CR; actuarial EFS in this subgroup was 61%. Myelosuppression occurred in all patients, with severe leukopenia (less than 1000/microliters) lasting a median of 12 days (range, 3 to 29 days); toxic deaths occurred in five patients (9%; 95% confidence interval, 4% to 19%). This intensive approach improved the response and survival of very poor risk non-Hodgkin's lymphoma patients.

Adult↗
PubMed1991

A brief-duration combination chemotherapy for elderly patients with poor-prognosis non-Hodgkin's lymphoma.

Curative combination chemotherapy is available for many patients with aggressive non-Hodgkin's lymphoma (NHL); however, treatment of elderly patients with these regimens is difficult due to excessive toxicity. From 1983 to 1988 the authors treated 26 patients 65 years and older with aggressive NHL with a novel 8-week chemotherapy regimen containing bleomycin, etoposide, cyclophosphamide, doxorubicin, methotrexate with leucovorin, and prednisone (BECALM), designed to preserve dose intensity and minimize toxicity. Median age was 75 years. Histologic types included the following: 20 intermediate grade (16 large noncleaved cell; two large cleaved cell; one intermediate grade, unspecified); six high grade (four small noncleaved cell; one immunoblastic sarcoma B-cell; one high grade, unspecified). Twenty-one patients were Stage III or IV. Twenty-two of 26 patients had one or more of the following: tumor greater than 10 cm; multiple extranodal sites; lactate dehydrogenase (LDH) 400 IU/l or greater; small noncleaved cell histologic type. Chemotherapy consisted of bleomycin 20 U intravenously (IV) weeks 1 and 7; etoposide 75 mg/m2 IV every day x 3 days on week 4; cyclophosphamide 600 mg/m2 IV weeks 1, 4, 7; doxorubicin 40 mg/m2 IV weeks 1, 7; methotrexate 50 mg/m2 IV weeks 1, 2, 4, 5, 7, 8 with oral leucovorin rescue; prednisone 60 mg orally for 10 days on weeks 1, 4, 7. Eighteen patients completed the 8-week treatment course. There were 13 complete responses (CR); seven patients remain in continuous CR at a median follow-up of 37.5 months. There have been five relapses, including one late relapse; and one patient died of an intercurrent illness in CR. Overall and actual event-free survivals are 38% and 27%, respectively. The major toxicities were neutropenic fever and mucositis. There were four treatment-related deaths. The authors conclude that BECALM chemotherapy can be administered to elderly patients with aggressive NHL. Although neurotoxicity and cumulative toxicity from bleomycin and anthracycline are avoided, the regimen remains moderately toxic, particularly with respect to myelosuppression. Treatment results compare favorably with other reported regimens in this group of patients with multiple poor prognostic features.

Aged↗
PubMed1991

Long-term survival in Ki-1 lymphoma.

Three patients with histologic and immunologic features of Ki-1-positive large cell lymphoma, who experienced long-term survival, are presented. These three patients at 2, 28, and 49 years of age had adenopathy; all cases had been initially misdiagnosed as metastatic carcinoma or malignant histiocytosis. On subsequent review, they had sinusal and diffuse growth of large pleomorphic cells that were Ber-H2 (Ki-1; CD 30) positive. One case marked as a T-cell lymphoma with UCHL1, one case expressed T-cell and B-cell markers, and one case was negative for both T-cell and B-cell markers. All patients received chemotherapy, and two received local radiation. One patient was not treated until 9 years after initial diagnosis. Two patients had several recurrences, but there has been no evidence of lymphoma in any of the three patients for 63 to 301 months; overall survival time has ranged from 14 to 25 years. These cases are the longest reported survivors with Ki-1 lymphoma; 5 years was the longest survival time previously reported. It also is noteworthy that Ber-H2 and other lymphoid-associated antigens appear to be preserved in formalin-fixed, paraffin-embedded tissues for prolonged periods. This may allow retrospective studies to evaluate the natural history of Ki-1 lymphomas, as well as their spontaneous or treatment-induced regression.

Adult↗
PubMed1991

Intensive chemotherapy with cyclophosphamide, carmustine, and etoposide followed by autologous bone marrow transplantation for relapsed Hodgkin's disease.

Fifty-six consecutive patients with advanced Hodgkin's disease considered incurable with further conventional chemotherapy were entered into a protocol that included high-dose cyclophosphamide (7.2 g/m2), carmustine (BCNU; 0.6 g/m2), and etoposide (VP16-213; 2.4 g/m2) (CBV) followed by autologous bone marrow transplantation (BMT). Prior combination chemotherapy had failed in all the patients, and all but five had been previously treated with both mechlorethamine, vincristine, procarbazine, and prednisone (MOPP) and doxorubicin, bleomycin, and vinblastine with or without dacarbazine (ABV[D]). Thirty-four eligible patients received short-course conventional chemotherapy and/or involved-field radiotherapy before CBV. However, formal restaging was not performed after these conventional therapies; ie, the therapies were not used to select responding patients for transplantation, and all who received such therapy subsequently received CBV and autologous marrow grafts. Forty-four patients (80%; 95% confidence interval [CI], 69% to 91%) achieved a complete response after CBV and BMT. Performance status at protocol entry and the use of conventional cytoreduction therapy before CBV correlated with response. Median follow-up is now 3.5 years (range, 2.5 to 5.0 years). Kaplan-Meier estimates for overall and event-free survival 5 years after transplant are 53% (95% CI, 37% to 67%) and 47% (95% CI, 33% to 60%), respectively. In a univariate analysis, patients with a normal performance status and those without constitutional ("B") symptoms at protocol entry had an improved overall and event-free survival. In a multivariate analysis, only a normal performance status remained significant. Disease progression occurred in 17 patients at an actuarial rate of 39% (95% CI; 26% to 56%) and occurred at previous sites of active disease in all but one patient; our analysis did not identify prognostic factors for progression. Toxic deaths, caused by either neutropenic sepsis or interstitial pneumonitis (IP), occurred in 12 patients (21%; 95% CI, 10% to 32%). CBV with autologous marrow support can produce durable remissions in a substantial number of patients with Hodgkin's disease considered incurable with conventional measures. Regimen refinements may even further improve the therapeutic index of BMT in this malignancy.

Adolescent↗
PubMed1991

Clinical features of 31 patients with Ki-1 anaplastic large-cell lymphoma.

Thirty-one patients were diagnosed by morphologic and immunophenotypic features as having primary Ki-1 anaplastic large-cell lymphoma (Ki-1 ALCL). the median age was 35 years (range, 4 months to 78 years); the male:female ratio was 18:13. B symptoms were observed in 13 patients. Peripheral adenopathy was present in 26 patients, while mediastinal adenopathy occurred in five. There was extranodal disease in 13 patients; the most common extranodal site was skin with seven affected. Seventeen patients had stage III/IV disease. Immunophenotypes were T cell in 24 patients and B cell in four patients; immunophenotype could not be determined in three patients. Cytogenetic abnormalities in chromosomes 2, 5, and 7 were detected in three patients. Although therapy was heterogeneous, the actuarial 2-year survival was 73%. Two-year disease-free survival was 39% for all patients; for stages I and II, it was 62% compared with 20% for stages III and IV (P = .001). Complete remission (CR) occurred in 21 of 23 patients receiving combination chemotherapy; however, nine relapses, including six of seven stage IV patients, occurred within 21 months of diagnosis. Preliminary observations suggest that Ki-1 ALCL may have a quiescent phase in the rare patient with only localized skin disease. However, the disease generally behaves as an intermediate- to high-grade lymphoma, and patients with Ki-1 ALCL should receive curative-intent combination chemotherapy.

Actuarial Analysis↗
PubMed1991

Effective treatment of small-noncleaved-cell lymphoma with high-intensity, brief-duration chemotherapy.

Small-noncleaved-cell (SNC) lymphoma is a high-grade, biologically aggressive neoplasm notable for poor response to therapy, high relapse rate, and less than a 20% long-term survival. We treated 20 patients with SNC lymphoma with a novel chemotherapeutic regimen using intensive doses of chemotherapy at frequent intervals in the inpatient setting. All patients were previously untreated. Sixteen patients (80%) had stage IV disease. Most patients (95%) had at least one other characteristic associated with poor prognosis (bulky [greater than 10 cm] disease, multiple extranodal sites, poor performance status), and 85% had two or more characteristics associated with poor prognosis. Seventeen patients (85%) achieved a complete response (CR) to therapy, including all three patients with human immunodeficiency virus (HIV)-associated disease. There have been three relapses, all occurring less than 18 months after treatment, and two of three relapses occurred in patients who were unable to complete therapy. At a median follow-up of 29 months, 13 patients (65%) remain disease-free; the calculated 5-year actuarial disease-free survival is 60%. Toxicity, chiefly myelosuppression, was severe but manageable. There were two treatment-related deaths, both in elderly patients with poor performance status and advanced-stage disease. These data suggest that such a dose-intensive approach improves the response and survival of patients with SNC lymphoma.

Adult↗
PubMed1991

Anaplastic large-cell Ki-1 malignant lymphomas. Recognition, biological and clinical implications.

Anaplastic large-cell Ki-1 lymphoma is defined by its characteristic histological appearance, reactivity with antibodies against CD30, and possibly by a chromosome marker t(2;5)(p23;q35). Because of its pleomorphic appearance, sinus distribution, and frequent reactivity with EMA, this lymphoma is often mistaken for other diseases such as metastatic carcinoma and malignant histiocytosis. The clinical features of this lymphoma are unusual and include a young median age and frequent extranodal disease with skin being a common site. Although remission is easily achieved, relapse is common and combination chemotherapy is suggested. The role of Ki-1 antigen in normal lymphocyte function, the cell of origin of anaplastic large-cell Ki-1 lymphoma, and its relationship to Hodgkin's disease are important questions that hopefully will be answered in the near future.

Antibodies↗
PubMed1990

Large-cell lymphomas: clinical and prognostic features.

We reviewed the clinical and pathologic features in 186 patients with large-cell lymphomas seen at Vanderbilt University Hospital between 1970 and 1986. Ninety-two cases (49%) were large noncleaved-cell lymphoma (LNCCL), 61 cases (33%) were large-cleaved-cell lymphoma (LCCL), 17 cases (9%) were peripheral T-cell lymphoma (PTCL), and 16 cases (9%) were immunoblastic sarcoma of B cells (IBS-B). These subsets of large-cell lymphoma did not differ with respect to median age, distribution by stage, or incidence of bone marrow involvement. Significant differences between groups were noted with regard to male:female ratio, incidence of symptoms, incidence of extranodal disease, and pattern of adenopathy. However, when LCCL was excluded from the analysis, none of these differences were significant. By univariate analysis, age, stage, marrow involvement, extranodal disease, B symptoms, elevated serum lactic dehydrogenase (LDH), and diffuse pattern were unfavorable prognostic features in large-cell lymphoma. However, when cases were stratified by cell of origin, nodular versus diffuse pattern was of no prognostic significance. Nodularity was favorable only because 71% of nodular and nodular-diffuse cases were LCCL, while the majority of diffuse cases were LNCCL. Although IBS-B is considered a "high-grade" lymphoma, we found no evidence for inferior survival in these patients compared with LNCCL or LCCL. In fact, survival was better in IBS-B than in LNCCL or LCCL, although this difference was not significant. However, survival was significantly inferior in PTCL (median, 11 months) compared with the other subsets of large-cell lymphoma (median, 46 months; P = .038, log-rank test). Since the association of PTCL and an inferior survival has most often been noted in the context of "second-generation" chemotherapy, we believe that this association may be therapy-dependent and may be minimized by the use of more aggressive chemotherapy regimens.

Actuarial Analysis↗
PubMed1990

Primary brain lymphoma in the immunocompetent host: relation to Epstein-Barr virus.

Epstein-Barr virus has been implicated in the pathogenesis of primary brain lymphoma in patients with congenital or acquired immunodeficiency states. To examine its role in central nervous system (CNS) lymphoma in the immunocompetent host, Epstein-Barr virologic studies were performed in six consecutive cases seen at our institutions. Virus DNA sequences were detected in only one of three tumor specimens studied by Southern blot hybridization. Serologic studies from the entire cohort disclosed past virus infection; however, antibody reactivity to virus-specific antigens in cerebrospinal fluid was limited to the patient harboring genome-positive tumor. Immunologic studies revealed hyperimmunoglobulin-E (range, 720 to 1040 micrograms/ml) in each of four patients tested. Our findings suggest that Epstein-Barr virus is an infrequent pathogen in nonimmunosuppressed patients with primary CNS lymphoma. Abnormalities in isotype-specific regulation of IgE production are common in such patients and may have pathogenetic implications.

Aged↗
PubMed1990

Monomorphic lymphomas arising in patients with Hodgkin's disease. Correlation of morphologic, immunophenotypic, and molecular genetic findings in 12 cases.

Patients with Hodgkin's Disease (HD) occasionally develop monomorphic lymphomas in which mononuclear cells, usually large in size, grow in sheets, and in which there are few reacting cells or classic Reed-Sternberg (RS) cells. Twelve patients of this type were reviewed to determine the nature of the monomorphic growth. Paraffin-embedded tissue sections from the original diagnostic HD and the monomorphic growths were stained for Leu-M1 (CD15), leukocyte common antigen (LCA, CD45), pan B-cell markers LN1, LN2, and L26, and pan T-cell marker UCHL1 (CD45R) reactive in paraffin-embedded tissues. Cases were included only if the original diagnostic material had the classic histopathologic features of HD, if there was a separate monomorphic growth (in place or time), and if sufficient materials from both phases were available for study. Original diagnoses of HD included nodular sclerosing (NS; 8 cases); lymphocyte predominant (LP; 2 cases); mixed cellularity (MC; 1 case); and lymphocyte depleted (LD: 1 case) types. RS cells in the eight cases of NS HD and one case of MC HD were generally Leu-M1 and LN2 positive, and L26, LN1, UCHL1, and LCA negative. RS cells in one case of NS HD were LCA positive in addition to Leu-M1, LN1, and LN2. Two cases of NS HD showed L26 positive RS cells. Conversely, RS cells and lymphocytic-histiocytic (L and H) variants in the cases of LP HD were Leu-M1 and LN2 negative, and LCA and LN1 positive. The one case of LD HD possessed RS cells that were negative for Leu-M1, but positive for LCA, L26, LN1, and LN2. In seven cases (4 NS, 2 LP, 1 LD) the monomorphic growths possessed a B-cell phenotype (LCA, L26, and LN1 positive; Leu-M1 and UCHL1 negative). In the remaining cases (4 NS, 1 MC), the monomorphic growths were Leu-M1 positive, and displayed phenotypes similar to the RS cells of the original NS HD. Southern blot analysis was performed on the monomorphic components of five cases and showed some form of immunoglobulin gene rearrangement in each (4 cases: rearranged heavy chain-joining region gene; 1 case: rearranged Mu chain-constant region gene). Two of these cases expressed L26 and LN1 in the monomorphic phases. Despite apparent immunoglobulin gene rearrangement, one case expressed T-cell antigens Leu-4 (CD3) and Leu-1 (CD5), in addition to Leu-M1 (CD15).(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1989

Peripheral T-cell lymphoma.

Peripheral T-cell lymphoma is the most common type of T-cell lymphoma seen in adults in the United States. Clinical data were reviewed from 134 cases of peripheral T-cell lymphoma diagnosed in three centers. The median age of the patients was 57 years (range, 4-97 years), 59% were male, and 36 patients (27%) had a history of a preceding disorder of the immune system. The tumors were grouped histologically into large cell (43%), mixed large and small cell (40%), and small cell (17%). The stage at diagnosis was I (7%), II (21%), III (22%), and IV (50%). B symptoms were present in 57%. The most frequent sites of extranodal involvement were bone marrow (35%), skin (13%), and lung (11%). Eighty patients were treated with a multiagent chemotherapy regimen with proven curative potential in aggressive non-Hodgkin's lymphomas and the remainder of the patients received less intensive chemotherapy (36 patients), radiotherapy (nine patients), or no treatment (nine patients). Fifty percent of the intensively treated patients achieved complete remission and the actuarial 4-year survival was 45%. However, the 4-year, disease-free survival in patients with Stage IV disease was only 10%. Although peripheral T-cell lymphomas appeared similar in many ways to their B-cell counterparts, disease-free survival by stage was low and patients with Stage IV disease had an especially poor outlook.

Adolescent↗
PubMed1989

Marrow involvement in cutaneous T-cell lymphoma. A clinicopathologic study of 60 cases.

Cutaneous T-cell lymphomas (CTCLs), including Sézary syndrome, are generally assumed to spare the marrow until the disease is far advanced. The authors reviewed marrow sections from 60 patients with CTCL, looking carefully for aggregates of cerebriform cells, and found marrow involvement in 13 patients (21.7%); another 19 had abnormal lymphoid nodules that were not diagnostic of involvement, and 28 had marrows with negative results. Involved marrows had nodules or infiltrates of dysplastic cerebriform cells that were often subtle, without a significant increase in cellularity; only one case showed massive involvement. Patients with CTCL with an infiltrative component of marrow involvement had associated peripheral blood involvement (eight of eight), generalized erythroderma (six of eight), lymph node involvement (five of eight), visceral progression (five of eight), and significantly shortened median survival compared with patients with CTCL with negative marrows (11 months and 70 months, respectively; P = 0.007). In contrast, five patients with nodules of tumor in the marrow but lacking an infiltrative component did not have peripheral blood involvement; only one patient had adenopathy or visceral progression develop, and two patients have died. Significant hematologic abnormalities were generally absent. Eight of 13 patients with marrow involvement had advanced skin disease, but skin disease was limited to plaques in five patients. Eight patients had marrow involvement develop within three months of initial diagnosis. Thus, marrow involvement occurs in approximately 20% of patients with CTCL, is often present at initial diagnosis, and is associated with widespread dissemination and shortened survival time when an infiltrative component is present.

Actuarial Analysis↗
PubMed1989

High-dose cytarabine and daunorubicin as consolidation therapy for acute myeloid leukemia in first remission: long-term follow-up and results.

In an effort to increase the proportion of patients with acute myeloid leukemia (AML) remaining in continued complete remission (CCR), we administered intensive postremission consolidation therapy with high-dose cytarabine (Ara-C) and daunorubicin. Eighty-seven patients, with a median age of 38 years (range, 7 to 71), received consolidation therapy after first complete remission was obtained with standard induction chemotherapy that included conventional doses of Ara-C. Consolidation therapy consisted of from one to three cycles of high-dose Ara-C (3 g/m2 intravenously [IV] over 1 hour every 12 hours for 12 doses) followed by daunorubicin (30 mg/m2/d IV bolus for 3 days). After completion of the high-dose Ara-C and daunorubicin, no further therapy was administered. Myelosuppression encountered with consolidation resulted in a median duration of neutropenia and thrombocytopenia of 3 weeks. Four patients (5%) died during consolidation due to infection and/or hemorrhage; 59% of patients experienced severe but nonfatal infectious or extramedullary organ toxicity. With a median follow-up of more than 3.5 years from diagnosis, the proportion of patients, by Kaplan-Meier product-limit estimate, remaining in CCR is 49% (95% confidence limits, 37% to 61%). In a Cox multivariate analysis, only age significantly (P less than .001) influenced the probability of remaining in CCR. The probability of remaining in CCR was 83%, 50%, and 23% for age groups of 25 or less, 26 to 45, and more than 45 years, respectively. These survival curves all have stable long-term plateaus, suggesting cure. In this study, the administration of brief, intensive nonmarrow ablative chemotherapy resulted in a large proportion of patients with AML remaining in CCR, results similar to those reported with allogeneic bone marrow transplantation. Relapse of acute leukemia was still the major reason for therapy failure, suggesting that more effective or additional postremission therapy will be required to further improve the likelihood of cure especially for older patients.

Adolescent↗
PubMed1988

Coupled spectrofluorometric assay for aminoglycoside phosphotransferases.

In order to make accurate kinetic measurements for the substrates of aminoglycoside (AG) phosphotransferases (APHs), we have developed an assay which overcomes many of the limitations of currently used assays. We have adapted the coupled spectrophotometric assay (P. R. Goldman and D. B. Northrop (1976) Biochem. Biophys. Res. Commun. 68, 230-236) for use in a spectrofluorometer. At an excitation wavelength of 340 nm, NADH will emit an intensity peak at 450 nm; NAD does not emit under these conditions. Our assay can accurately measure differences of 0.25 microM. For the APH(3')-II encoded on Tn5, we have redetermined the Km's for the AGs, amikacin (AK), kanamycin (KM), and ribostamycin (Rib), and for ATP. Our values for AK (76 microM) were lower than those derived from the spectrophotometric assay; for KM and Rib we obtained Km values of 5.1 and 3.6 microM, respectively. These values were well below the limit of accuracy (10 microM) for the spectrophotometric assay. In addition, we have begun characterization of an APH from a clinical isolate with a low Km for AK. Thus far, we have determined that this enzyme has Km's of approximately 1 microM for both AK and KM. These results show that the assay is well suited for accurate determinations of kinetic constants for low Km substrates of APH enzymes.

Drug Resistance, Microbial↗
PubMed1988

T4+ (helper phenotype) chronic lymphocytic leukemia: case report with liver failure and literature review.

T-cell lymphomas and leukemias are a heterogeneous group of neoplasms found in each anatomic compartment of the T system (marrow, thymus, and various peripheral tissues) and that have varying phenotypic expressions. Histopathologic features of the thymic and peripheral T neoplasms do not fit into a clearly defined pattern, and clinical expressions of T neoplasms are likewise variable. This report describes a 60-year-old man with "chronic" lymphocytic leukemia of T4+ (helper) phenotype. Rapid deterioration in liver function, presumably due to tumor infiltration, was unexpected and has not previously been reported. The unusual clinical and pathologic features are reviewed in the context of T-cell neoplasms, particularly T4+ processes.

Humans↗