Mefenoxam-Resistant Isolates of Pythium irregulare in an Ornamental Greenhouse in California.

Root rot, caused by Pythium species, is a common malady in ornamental greenhouses in Monterey County, CA. In 2001, a root rot of Gerbera daisy (Gerbera jamesonii) and lisianthus (Eustoma grandiflora) caused plant losses in excess of 15 and 75%, respectively, in one greenhouse. Some plantings were total losses. Although mefenoxam was used repeatedly, no disease control was reported. P. irregulare was identified based on morphological structures produced on grass blades in water (1) and on the sequence of the rDNA internal transcribed spacer (ITS) region. Four isolates from each host were tested for sensitivity to mefenoxam in a laboratory bioassay. Using corn meal agar amended with mefenoxam at 0, 0.1, 1, 10, 50, or 100 µg a.i./ml, no inhibition of growth of any isolate occurred at concentrations of 10 µg/ml or less. At 50 and 100 µg/ml, radial growth of colonies was inhibited by approximately 20%. In contrast, 26 isolates of P. ultimum from various agricultural soils in California were completely inhibited by mefenoxam at 100 µg a.i./ml. At 0.1, 1, 10, and 50 µg/ml, growth of these isolates was inhibited by 33, 61, 78, and 96%, respectively. Each treatment was replicated three times, and the experiment was repeated with similar results. Mefenoxam was introduced in 1996 to replace metalaxyl. While metalaxyl contains a mixture of active and inactive enantiomers, mefenoxam contains only the active enantiomer. The intensive use of metalaxyl and mefenoxam in this greenhouse may have resulted in selection for resistant isolates. A resistant isolate (8-007 from Gerbera) has been submitted to the American Type Culture Collection: Manassas, VA. Reference: (1) A. J. van der Plaats-Niterink. Monograph of the Genus Pythium. Stud. Mycol. No. 21. Centraalbureau voor Schimmelcultures, Baarn, the Netherlands, 1981.

B-cell surface phenotypes of proliferating myeloma cells: target antigens for immunotherapy.

Dual-parameter flow cytometric analysis of B-cell antigens and DNA content was used to determine the phenotypes of proliferating tumor cells (S-phase cells) from 30 patients with multiple myeloma. B4 (CD19), J5 (CALLA, CD10), B1 (CD20), and monotypic surface immunoglobulin (Slg) were expressed heterogeneously in 24 patients. J5 and monotypic Slg were found most frequently but were always expressed on a significantly lower percentage of cells than the antigens typically associated with plasma cells, cytoplasmic immunoglobulin (Clg) and T10 (CD38). S-phase cells were found in each antigen(+) subset. B antigen(+) cycling cells were demonstrated in 16 patients whose marrow or blood cells expressed B antigens exclusively in the hyperdiploid fraction and therefore were certainly part of the myeloma clone. Similar to the low level of proliferative activity of the T10(+), Clg(+), and PCA1(+) subsets, the percentages of cycling cells of the preplasma cell B-antigen-bearing myeloma subsets ranged from less than 1% to 12%. The tumor cells of four patients were also studied with dual-color surface antigen analysis and demonstrated independent expression of B antigens, with only rare coexpression of T10 and monotypic Slg, J5, or B4. These findings are consistent with the presence of distinct myeloma subsets bearing differing B phenotypes in the same tumor and provide evidence that the proliferation in myeloma is occurring at various developmental stages in the malignant B lineage. These antigens may be important targets for immunologic therapy aimed at eliminating the entire proliferating compartment of this B-cell tumor.

Light resistance and stretching exercise in elderly women: effect upon strength.

Forty-seven elderly women (63 to 88 years of age, mean = 71 years) were studied to determine the effect of a 25-week light resistance and aerobic exercise program upon arm and leg strength. Three groups were formed: nonexercising controls (C, n = 12), exercise (EN, n = 18) and exercise with light weights on on the wrists and ankles (EW, n = 17). Exercise was performed for one hour, three times/week. Subjects were pretested and posttested for maximal isokinetic muscle strength (angular velocity 60 degrees/sec) for elbow flexion and extension, shoulder internal and external rotation, and knee flexion and extension. Dunn planned contrasts were used to compare C vs exercise groups combined (EN + EW) and EN vs EW. No significant differences were found among groups at baseline. EN + EW improved significantly (p less than 0.05) more than C in elbow extension (17%), shoulder internal rotation (14%), shoulder external rotation (9%), and knee flexion (20%). No significant differences were found between EN and EW. These data indicate that elderly women can achieve substantial gains in the strength of arm and leg musculature as a result of regular light resistance and aerobic exercise, but that the use of light weights on the wrists and ankles for added resistance did not enhance this effect.

Hemoglobin SC disease and alpha-thalassemia. Prolonged survival and mild clinical course.

An 86-year-old black woman admitted for an elective cataract extraction was found to have moderate hypochromic microcytic anemia. Hematologic evaluation disclosed the presence of hemoglobin SC disease and heterozygous alpha-thalassemia-2 (alpha alpha/alpha-). A red cell density profile of the patient's peripheral blood revealed an absence of the typical uniform shift toward higher-density values seen in hemoglobin SC disease, indicating a "normalization" in the distribution of intracellular hemoglobin types. It is suggested that the co-inheritance of hemoglobin SC disease and heterozygous alpha-thalassemia-2, probably by decreasing the tendency toward intracellular hemoglobin S polymerization, contributed to her prolonged survival and relatively mild clinical course.

Acquired pure red cell aplasia associated with chronic lymphocytic leukemia.

Pure red cell aplasia (PRCA) represents selective failure of erythropoiesis in the absence of abnormalities in leukopoiesis or thrombocytopoiesis. Acquired PRCA has occurred uncommonly in chronic lymphocytic leukemia (CLL). We report six patients with non-T-cell CLL in which nine episodes of PRCA were observed. In six of the nine episodes, the patients had received recent oral alkylating agents; conversely, recovery from aplasia occurred in some while on alternate alkylator therapy and two patients had no pretreatment. Spontaneous occurrence and recovery, therefore, could not be excluded. Onset of PRCA may be suggested by macrocytosis, but discontinuance of therapy at its development may not prevent PRCA if, indeed, therapy is one of the causes. Supportive therapy or alkylators and prednisone permitted recovery without mortality in all six patients. The interval between onset of CLL and the recognition of first PRCA episode varied from one month to nine years (mean, 5.3 years); the duration of PRCA ranged from three to nine months (mean, 4.7 months). In addition to previously better understood causes of anemia in CLL, the uncommon occurrence of PRCA is an additional consideration in the differential diagnosis of sudden anemia in CLL.

Prolymphocytic leukemia. Response to asparaginase.

A 69-year-old woman previously diagnosed as having chronic lymphocytic leukemia had a lymphocyte count of 1,500 X 10(9)/L develop. Bone marrow and peripheral blood lymphocyte morphology and lymphocyte surface markers were consistent with the diagnosis of prolymphocytic leukemia of the null cell type. The leukemia was resistant to management with alkylating agents, combination chemotherapy including doxorubicin hydrochloride, or leukapheresis. The addition of asparaginase to the previously ineffective prednisone and vincristine sulfate therapy produced a dramatic response during a two-week period with a decrease in the peripheral lymphocyte count from 980 X 10(9) to 20 X 10(9)/L and a return toward normal of the concentration of polymorphonuclear leukocytes. Previously, there has been only infrequent or transient benefit from treatment provided these patients from regimens including chemotherapy, splenectomy, irradiation, and leukopheresis. It is suggested that asparaginase be considered as initial induction therapy for this disease process.

Current transfusion practices.

Utilization of packed red blood cells (PRBC) and plasma components individually or in combination allows replacement of the precise blood element needed, while avoiding some of the potential hazards of whole blood transfusions. Transfusion of PRBC, rather than whole blood, reduces the risk of circulatory overload and nonhemolytic transfusion reactions. Frozen PRBC essentially eliminate leukocyte or platelet sensitization and transmission of hepatitis is extremely rare.