Anthrax lethal factor inhibition.

The primary virulence factor of Bacillus anthracis is a secreted zinc-dependent metalloprotease toxin known as lethal factor (LF) that is lethal to the host through disruption of signaling pathways, cell destruction, and circulatory shock. Inhibition of this proteolytic-based LF toxemia could be expected to provide therapeutic value in combination with an antibiotic during and immediately after an active anthrax infection. Herein is shown the crystal structure of an intimate complex between a hydroxamate, (2R)-2-[(4-fluoro-3-methylphenyl)sulfonylamino]-N-hydroxy-2-(tetrahydro-2H-pyran-4-yl)acetamide, and LF at the LF-active site. Most importantly, this molecular interaction between the hydroxamate and the LF active site resulted in (i) inhibited LF protease activity in an enzyme assay and protected macrophages against recombinant LF and protective antigen in a cell-based assay, (ii) 100% protection in a lethal mouse toxemia model against recombinant LF and protective antigen, (iii) approximately 50% survival advantage to mice given a lethal challenge of B. anthracis Sterne vegetative cells and to rabbits given a lethal challenge of B. anthracis Ames spores and doubled the mean time to death in those that died in both species, and (iv) 100% protection against B. anthracis spore challenge when used in combination therapy with ciprofloxacin in a rabbit "point of no return" model for which ciprofloxacin alone provided 50% protection. These results indicate that a small molecule, hydroxamate LF inhibitor, as revealed herein, can ameliorate the toxemia characteristic of an active B. anthracis infection and could be a vital adjunct to our ability to combat anthrax.

Thrombosis related to the use of L-asparaginase in adults with acute lymphoblastic leukemia: a need to consider coagulation monitoring and clotting factor replacement.

L-asparaginase (L-asp) has become an important component of combination chemotherapy for acute lymphoblastic leukemia (ALL). However, L-asp can produce depletions in many of the clotting factors with an associated risk for thrombosis and hemorrhage. Three consecutive patients seen at the Mayo Clinic with L-asp related thrombosis are described and an in-depth review of the literature is provided. Two of the 3 patients developed central nervous system (CNS) complications with evidence of thrombosis and hemorrhagic infarction. Two of the patients also developed extensive upper extremity thrombosis. The results of comprehensive hemostatic surveys showed marked abnormalities in all 3 patients. Many of the thrombotic complications related to L-asp involve the CNS, as illustrated in 2 of our patients. These patients should be treated aggressively since full recovery is possible. The precise cause of thrombosis is yet to be determined but is likely multifactorial. The optimal treatment and prevention of thrombosis in this group of patients remains poorly defined.

Human babesiosis.

OBJECTIVE: To describe a case of human babesiosis and review the literature on the disease. MATERIAL AND METHODS: We describe a 62-year-old man with babesiosis, outline his clinical course and response to therapy, and discuss the use of the polymerase chain reaction for the diagnosis and monitoring of the infection. RESULTS: The onset of the disease was insidious, with fatigue, fever, weight loss, intermittently discolored urine, and anemia. Computed tomography of the abdomen revealed a small, shrunken spleen with an irregular border. With treatment, the symptoms gradually resolved. Although peripheral blood smears were negative soon after therapy, Babesia microti DNA was detected by polymerase chain reaction 53 days after initial examination. CONCLUSION: The development of improved methods for diagnosis, including indirect immunofluorescent antibody assays and the polymerase chain reaction, provides more sensitive detection of the parasitemia associated with babesiosis. Use of these methods may help to delineate the complete clinical spectrum of this infection and its geographic distribution in the United States.

Secondary T-cell lymphoma in the setting of nodular lymphocyte predominance Hodgkin's disease.

Lymphocyte predominance Hodgkin's disease (LPHD) can be histologically subdivided into a nodular and diffuse variety. The two subtypes differ in immunophenotypic characteristics but have a similar long-term clinical outcome. Nodular LPHD has immunophenotypic and histological characteristics suggestive of a B-cell derived neoplastic process. Nodular LPHD is associated with an increased risk of secondary large cell lymphoma (LCL). Gene rearrangement studies in some of these cases have revealed a B-cell clonal process, further supporting the association between nodular LPHD and the B-cell system. In addition, it has been suggested that the apparent secondary LCL, at least in some cases, may represent a histologic progression of nodular LPHD. We report a unique case of T-cell lymphoma, confirmed by T-cell receptor gene rearrangement studies, which developed in the setting of nodular LPHD. Our observation demonstrates that the association of nodular LPHD and LCL is complex and that LCL developing in the context of nodular LPHD may be an independent secondary process sometimes involving T-cell lymphomas.

Polymicrobial cholangitis and Kaposi's sarcoma in blood product transfusion-related acquired immune deficiency syndrome.

Before presenting to the Mayo Clinic, a 24-year-old white woman had received 35 transfusions of blood products over a 72-hour period in February 1981. Two and one half years later, the diagnosis of polymicrobial cholangitis (Cryptosporidium, Candida albicans, and Klebsiella pneumoniae) was established. Further evaluation demonstrated profound helper T lymphocyte suppression, disseminated Mycobacterium avium-intracellular infection with mycobacteremia, and Kaposi's sarcoma of lymphoid tissue, confirming a diagnosis of acquired immune deficiency syndrome (AIDS). This case represents an unusual infectious complication of AIDS. Additionally, this is believed to be the first report of Kaposi's sarcoma occurring in a patient with AIDS associated with blood product transfusion.

T-cell chronic lymphocytic leukaemia: anomalous cell markers, variable morphology, and marked responsiveness to pentostatin (2'-deoxycoformycin).

4 men with an unusual variant of T-cell chronic lymphocytic leukaemia are reported. The clinical features differed from the virus-associated T-cell disease reported from Japan, the Caribbean, and the southeastern United States. Cytology was pleiomorphic: cells with cerebriform nuclei resembling Sézary cells and lymphocytes with cytoplasmic granules resembling T-suppressor cells occurred in the same patients. Immunofluorescence studies with monoclonal antibodies suggested that the leukaemia cells expressed determinants of both helper- (OKT4+) and suppressor-(OKT8+) related antigens. The cells were TdT-negative. In all patients the disease was very refractory to conventional cytotoxic agents, but there was prompt and extensive response to the adenosine deaminase inhibitor pentostatin (2'-deoxycoformycin). This agent merits further study in the treatment of T-cell chronic lymphocytic leukaemia.

Analysis of human leukemic cells by use of high-resolution two-dimensional electrophoresis. I: results of a pilot study.

We analyzed mononuclear leukocytes from patients with various human leukemias by high-resolution two-dimensional electrophoresis. Tumor cells of the granulocytic, monocytic, and lymphoid lineages [obtained from chronic granulocytic leukemia in blast transformation, acute monocytic leukemia, and chronic lymphocytic leukemia (CLL), respectively] can be easily recognized by using a series of cell-type marker proteins identified by comparison of fractionated normal cell populations. B and T cell types of CLL could be distinguished, the results correlating well with those obtained by use of monoclonal-antibody staining methods. In two cases representing almost pure B-cells (classical CLL; 0% T, 85% B) and T-cells (cutaneous T-cell leukemia; 77% T, 0% B), 27 of 29 marker proteins showed quantitative B/T differences comparable to those observed in comparisons of normal B-and T-lymphocytes prepared by cell sorting. These results indicate that cells from relatively well-differentiated leukemias show complex patterns of gene expression very similar to those of the corresponding normal cells and strongly support the use of large marker panels in cell-type determination. Less-well-differentiated acute leukemias [such as acute undifferentiated and acute granulocytic (FAB:M1)] appear to yield protein patterns corresponding less closely to recognizable mature cell types, and may show expression of novel proteins related to the state of differentiation.

Hematologic malignancies occurring in patients with urticaria pigmentosa.

Six patients had hematologic malignancies and coincident urticaria pigmentosa, five with the disseminated maculopapular form and one with the plaque form. Two patients had the juvenile-onset variety; the remainder had the adult eruptive variety. None of the patients complained of symptoms that could be attributed to liberation of histamine. In the two patients with juvenile-onset urticaria pigmentosa, the hematologic malignancies developed at the age of 17 years; one had Hodgkin's disease, and the other had acute myelomonocytic leukemia. In three patients with adult eruptive urticaria pigmentosa, the cutaneous lesions developed within 12 months of the diagnoses of lymphocytic lymphoma (two patients) and evolving myelomonocytic leukemia (one patient). In the remaining patient, cutaneous lesions developed many years before chronic lymphocytic leukemia was diagnosed. None of the patients had systemic mastocytosis. Skin biopsy specimens from all six patients showed an increase in dermal and perivascular round cells, and mast cells were seen in specimens from five of the six patients. In patients who received cytotoxic drugs for the hematologic malignancy, there was no change in the urticaria pigmentosa.

Use of computed tomography in diagnosis of soft-tissue tumors.

Soft-tissue tumors can evade the usual diagnostic methods. In the case presented, computed tomography proved to be the best diagnostic tool in demonstrating a malignant extranodal lymphoma. Computed tomography is useful not only in detecting a tumor but also in determining its extent. This aids the surgeon in selecting and conducting the most appropriate operation.

Mycosis fungoides evolving to myelomonocytic leukemia.

Acute myelomonocytic leukemia, a type of leukemic conversion that may be a manifestation of mycosis fungoides, developed in two patients with fairly typical courses of mycosis fungoides. The cases of five other patients with myelogenous leukemia as the terminal event of mycosis fungoides have been reported in the literature. A relationship to therapy could not be established, although all patients had had irradiation or chemotherapy or both.