ALBERT

Description: In tropical areas, where unsupervised use of antimalarial drugs is common, patients with an illness consistent clinically with severe malaria but with negative blood smears pose a management dilemma. Malaria pigment is evident in peripheral blood leukocytes in greater than 90% of patients with severe malaria. To characterize the clearance kinetics of parasitized erythrocytes and malaria pigment-containing leukocytes, sequential peripheral blood and intradermal smears were assessed in 27 adult Vietnamese patients with severe falciparum malaria. The clearance of parasitized erythrocytes and pigment-containing monocytes (PCMs) followed first order kinetics. The elimination of pigment-containing neutrophils (PCNs) was first order initially, but deviated from this when counts were low. Clearance of peripheral blood PCMs (median clearance time, 216 hours; range, 84 to 492 hours) was significantly slower than that of parasitized erythrocytes (median, 96 hours; range, 36 to 168 hours) or PCNs (median, 72 hours; range, 0 to 168 hours; P 〈 .0001). Intradermal PCM clearance times were the longest of all (median, 12 days; range, 6 to 23 days; significantly longer than peripheral blood PCM clearance, P 〈 .001). Twenty-one (88%) patients still had signs, symptoms, or laboratory features of severe malaria after parasite clearance but before phagocyte pigment clearance. Sixteen of the 23 surviving patients (70%; 95% confidence interval, 50% to 87%) still had intraleukocytic malaria pigment on peripheral blood films 72 hours after parasite clearance. Thus, by determining the distribution of malaria pigment in peripheral blood and intradermal phagocytes, the time since effective antimalarial treatment started can be estimated. Microscopy for intraleukocytic pigment is valuable in the differential diagnosis of severe febrile illnesses in malarious areas where uncontrolled use of antimalarial drugs is widespread.

Description: We have studied the role of factor VIII-von Willebrand factor (FVIII- vWF) in both platelet adherence to subendothelium and ristocetin- induced platelet aggregation using monoclonal antibodies to human FVIII- vWF. Twenty-five monoclonal antibodies were obtained, two of which were directed to the factor VIII moiety of FVIII-vWF; one of these two completely inhibited the procoagulant activity (FVIII:C). The remaining 23 monoclonal antibodies were directed to the von Willebrand factor moiety of FVIII-vWF. The ability of the latter monoclonal antibodies to inhibit platelet adherence to arterial subendothelium was investigated with a perfusion model. According to the number of platelets adhering to the subendothelium, three groups of monoclonal antibodies could be discerned: (A) antibodies not affecting platelet adherence; (B) antibodies that inhibited platelet adherence to the level as observed when von Willebrand's disease plasma was tested; and (C) antibodies that completely inhibited both platelet adherence to subendothelium and ristocetin-induced platelet aggregation. The two antibodies present in group C competed for the same or closely related epitope(s) present on FVIII-vWF. These results demonstrate that a domain is present on the FVIII-vWF molecule that is associated both with ristocetin-induced aggregation and with the ability of FVIII-vWF to support platelet adherence to the subendothelium. Based on these observations, it is concluded that ristocetin-induced binding of FVIII-vWF to platelets reflects, at least in part, a physiologic mechanism regulating the function of FVIII-vWF in primary hemostasis.

Description: Restriction endonuclease mapping defined a partial deletion of about 1.35 kb in the beta-globin gene of a black American patient with hemoglobin S-beta zero-thalassemia and in his uncle with a beta zero- thalassemia trait. The 5′ endpoint of the deletion is about 600 bases upstream from the cap site, and the 3′ endpoint lies within about 500 bases from the 5 splice junction of the second intervening sequence. The deletion is different from that of a previously reported Indian beta zero-thalassemia allele, where 0.6 kb is deleted at the 3′ end of the beta-globin gene.

Description: The production of colony-stimulating factor (CSF) by the peripheral blood cells of untreated patients with acute myeloid leukemia (AML) was measured in the agar culture system using normal human bone marrow as the source of colony-forming units (CFUc). CSF production was found to be variable and was related to the morphologic subtype of AML--cells from patients with monocytic leukemia produced normal or large quantities of CSF, while (with one exception) those from patients with myeloblastic leukemia produced little or no CSF. There was a general relationship between CSF production and serum lysozyme levels. Attempts to demonstrate a consistent inhibitory effect exerted by leukemic peripheral blood cells on normal leukopoiesis in vitro were negative. Results instead suggested that the addition to the feeder layer of cells from patients with monocytic leukemia could raise CSF levels above those obtained with normal peripheral blood leukocytes alone, possibly by recruiting additional CFUc from normal marrow.

Description: The production of colony-stimulating factor (CSF) by the peripheral blood cells of untreated patients with acute myeloid leukemia (AML) was measured in the agar culture system using normal human bone marrow as the source of colony-forming units (CFUc). CSF production was found to be variable and was related to the morphologic subtype of AML--cells from patients with monocytic leukemia produced normal or large quantities of CSF, while (with one exception) those from patients with myeloblastic leukemia produced little or no CSF. There was a general relationship between CSF production and serum lysozyme levels. Attempts to demonstrate a consistent inhibitory effect exerted by leukemic peripheral blood cells on normal leukopoiesis in vitro were negative. Results instead suggested that the addition to the feeder layer of cells from patients with monocytic leukemia could raise CSF levels above those obtained with normal peripheral blood leukocytes alone, possibly by recruiting additional CFUc from normal marrow.

Description: Lytic bone involvement in primary systemic (AL) amyloidosis is uncommon. To-date, there is no systematic study of bone metabolism in patients with AL amyloidosis. For this reason, we evaluated prospectively 102 patients with previously untreated AL amyloidosis who were diagnosed between January 2000 and June 2008 in the Plasma Cell Dyscrasias Unit of the Department of Clinical Therapeutics (Athens, Greece). All patients had histologically confirmed AL amyloidosis, while the definition of organ involvement, hematological and organ response and progression were based on consensus criteria. The levels of the following bone remodeling indices were measured before the administration of any kind of therapy: i) osteoclast regulators: soluble receptor activator of nuclear factor-kappaB ligand (sRANKL), osteoprotegerin (OPG), chemokine C-C motif ligand 3 (CCL-3, previously known as MIP-1alpha) and osteopontin; ii) bone resorption markers: C- and N- telopeptide of type-1 collagen (CTX and NTX, respectively) and tartrate resistant acid phosphatase type-5b; iii) bone formation markers: bone-alkaline phosphatase and osteocalcin. The results were compared with those of 35 age- and gender-matched healthy controls, 40 patients with monoclonal gammopathy of undetermined significance (MGUS) and 35 newly diagnosed, untreated patients with symptomatic multiple myeloma (MM). The median age of AL patient was 65 years (range: 39-80 years); 43% were males; 60% had heart involvement, 73% renal involvement, 11% liver involvement and 40% had peripheral/autonomous nerve system involvement; 67% of patients had two or more organs involved; 16% had a baseline serum creatinine 〉2 mg/dl. The median serum albumin was 3.2 g/dl, the median serum β2-microglobulin was 1.8 mg/L and the median 24h urine protein was 3350 mg/24h. Median NT-proBNP was 1954 pg/ml; 26%, 41% and 33% of patients were Mayo stage -1, -2 and -3, respectively. None of AL patients had lytic bone lesions in plain radiography or other features suggestive of MM, such as hypercalcemia, significant anemia unrelated to renal impairment or predominant Bence-Jones proteinuria. Bone resorption (assessed by CTX or NTX) in AL-patients was increased (p

Description: The unstable hemoglobin Montreal with a deletion of three amino acid residues (Asp, Gly, Leu) at positions 73, 74, and 75 of the beta chain and an insertion of four residues (Ala, Arg, Cys, Gln) at the same location was observed in a 7-year-old Canadian boy suffering from a moderate hemolytic anemia. The introduction of an extra amino acid residue and of other changes in the crevice where the heme group is located is the likely cause of the instability of this hemoglobin variant. The above listed changes were detected through analyses of tryptic peptides of the beta-Montreal chain, sequencing of amplified DNA, and hybridization of amplified DNA with appropriate, 32P-labeled, oligonucleotide probes. It is suggested that a mispairing involving the AGTG sequences at codons 66 and 67 and at codons 72 and 73 of the normal beta gene caused a repetition of a 16-bp segment, while a deletion of 10 nucleotides due to recombination or slippage followed by a second short deletion during DNA repair resulted in the modified sequence of the beta-Montreal gene.

Description: “Fetal” erythrocytes are present in older children and certain adults with hematologic disorders. To determine if regenerating bone marrow produces such cells, we examined the blood of seven allogeneic bone marrow transplant recipients. Six patients were engrafted with donor cells, while on e patients recovered autologous bone marrow after rejection of a marrow transplant. All seven patients had fetal hemoglobin levels of up to 10% by 100 days after transplant. In three patients, the Ggamma to Agamma ratio in the fetal hemoglobin was “newborn”, while in one it was “adult”. Gamma chain synthesis in blood and bone marrow never exceeded 20% of total non-alpha globin synthesis. The fetal hemoglobin was heterogeneously distributed in the cells. High titer i antigen also appeared. All fetal characteristics declined by 200 days. Erythropoiesis during bone marrow recovery appears to be associated with an accelerated, albeit partial, recapitulation of ontogeny.

Description: Two leukemic cell lines (697 and 207) were established from bone marrow cells obtained from children with ALL in relapse. These cell lines were positive for the common-ALL antigen (CALLA), the HLA-DR (i.e., Ia-like) antigen, and for cytoplasmic and surface IgM heavy chains. The lines were negative for other immunoglobulin heavy chains and light chains. The lines had elevated levels of terminal deoxynucleotidyl transferase enzyme and expressed surface antigens found on normal myeloid- macrophage cells (MMA) and on natural killer cells (HNK-1). A minority of cells in line 207 expressed the T-1, T-6, and Leu-1 antigens as detected by monoclonal antibodies. Line 697 was positive for Epstein- Barr virus (EBV), while line 207 did not possess EBV. Line 697 carried a marker chromosome (identified as a translocation between chromosomes 7 and 19), which was also patient's fresh leukemic cells. The leukemic origin of the cell lines was further indicated by their morphological, cytochemical, and immunologic similarity to the patients' leukemic cells. Phenotypically, both cell lines appear to be arrested in a transitional stage of development between pre-B and B cells and express surface antigens usually found on normal and fresh leukemic cells of non-B-cell lineages.

Description: Actin is an important cytoskeletal protein; new actin synthesis occurs during differentiation of many motile cells. To better understand the process of myeloid maturation, the change in actin content during induced maturation of HL-60 human promyelocytic leukemia cells was studied. HL-60 cells induced toward myeloid maturation by a 5-day exposure to dimethylformamide showed an 86% increase in a 43,000 mol wt protein comigrating with rabbit muscle actin on dodecyl sulfate polyacrylamide gels. To further demonstrate that this was an increase in actin content, the total actin content of lysed HL-60 cells was measured by the ability of actin to inhibit DNAase I. Using this assay, actin content of HL-60 cells increased 96% during induced differentiation. The amount of incorporation of 3H-leucine into actin doubled after a 5-day exposure to dimethylformamide, suggesting the increase in actin was due primarily to new synthesis. Total new protein synthesis increased 2–7-fold during differentiation. Additional analysis of polyacrylamide gels showed increased quantities and new synthesis of a high molecular weight protein comigrating with rabbit muscle myosin. This study shows that actin content increases during myeloid maturation. It also demonstrates that the HL-60 cell line is a useful model to study both functional and biochemical events during human myeloid differentiation.