P53 gene mutations in acute myeloid leukemia with 17p monosomy

We looked for mutations of exons 5 to 8 of the P53 gene in 10 patients with acute myeloid leukemia (AML) and 17p monosomy, and 36 patients with AML and no cytogenetic abnormalities of 17p. DNA was analyzed by polymerase chain reaction, single-strand conformation polymorphism analysis, and nucleotide sequencing. Four of the 10 patients with 17p monosomy showed point mutation, single-nucleotide deletion, or insertion in exons 7 or 8. By contrast, only 1 of the 36 patients with AML and no cytogenetic abnormalities of 17p showed a mutation of the P53 gene in exons 5 to 8 (P less than .01). These results suggest that alterations of the P53 gene may have a role in leukemogenesis in some cases of AML. The fact that P53 gene mutations occurred more often in patients with 17p monosomy seems to support the "recessive" model of tumor suppressive activity of the P53 gene rather than the "dominant" model, in which alteration of only one allele is sufficient for the development of malignancy.     

Adoptive immunotherapy evaluating escalating doses of donor leukocytes for relapse of chronic myeloid leukemia after bone marrow transplantation: separation of graft-versus-leukemia responses from graft-versus-host disease

Infusions of large numbers (> 10(8)/kg) of donor leukocytes can induce remissions in patients with chronic myeloid leukemia (CML) who relapse after marrow transplantation. We wanted to determine if substantially lower numbers of donor leukocytes could induce remissions and, if so, whether this would reduce the 90% incidence of graft-versus-host disease (GVHD) associated with this therapy. Twenty-two patients with relapsed CML were studied: 2 in molecular relapse, 6 in cytogenetic relapse, 10 in chronic phase, and 4 in accelerated phase. Each patient received escalating doses of donor leukocytes at 4- to 33-week intervals. Leukocyte doses were calculated as T cells per kilogram of recipient weight. There were 8 dose levels between 1 x 10(5) and 5 x 10(8). Lineage-specific chimerism and residual leukemia detection were assessed using sensitive polymerase chain reaction (PCR) methodologies. Nineteen of the 22 patients achieved remission. Remissions were achieved at the following T-cell doses: 1 x 10(7) (n = 8), 5 x 10(7) (n = 4), 1 x 10(8) (n = 3), and 5 x 10(8) (n = 4). To date, 15 of the 17 evaluable patients have become BCR-ABL negative by PCR. The incidence of GVHD was correlated with the dose of T cells administered. Only 1 of the 8 patients who achieved remission at a T-cell dose of 1 x 10(7)/kg developed GVHD, whereas this complication developed in 8 of the 11 responders who received a T-cell dose of > or = 5 x 10(7)/kg. Three patients died in remission, 1 secondary to marrow aplasia, 1 of respiratory failure and 1 of complications of chronic GVHD. Sixteen patients who were mixed T-cell chimeras before treatment became full donor T-cell chimeras at the time of remission. Donor leukocytes with a T-cell content as low as 1 x 10(7)/kg can result in complete donor chimerism together with a potent graft-versus-leukemia (GVL) effect. The dose of donor leukocytes or T cells used may be important in determining both the GVL response and the incidence of GVHD. In many patients, this potent GVL effect can occur in the absence of clinical GVHD.     

Annexin V for flow cytometric detection of phosphatidylserine expression on B cells undergoing apoptosis

Apoptosis, or programmed cell death, is a general mechanism for removal of unwanted cells from the immune system. It is characterized by chromatin condensation, a reduction in cell volume, and endonuclease cleavage of DNA into oligonucleosomal length fragments. Apoptosis is also accompanied by a loss of membrane phospholipid asymmetry, resulting in the exposure of phosphatidylserine at the surface of the cell. Expression of phosphatidylserine at the cell surface plays an important role in the recognition and removal of apoptotic cells by macrophages. Here we describe a new method for the detection of apoptotic cells by flow cytometry, using the binding of fluorescein isothiocyanate-labeled annexin V to phosphatidylserine. When Burkitt lymphoma cell lines and freshly isolated germinal center B cells are cultured under apoptosis inducing conditions, all cells showing chromatin condensation strongly stain with annexin V, whereas normal cells are annexin V negative. Moreover, DNA fragmentation is only found in the annexin V-positive cells. The nonvital dye ethidium bromide was found to stain a subpopulation of the annexin V-positive apoptotic cells, increasing with time. Our results indicate that the phase in apoptosis that is characterized by chromatin condensation coincides with phosphatidylserine exposure. Importantly, it precedes membrane damage that might lead to release from the cells of enzymes that are harmful to the surrounding tissues. Annexin V may prove important in further unravelling the regulation of apoptosis.     

Autopsies of sudden infant death syndrome—classification and epidemiology

An enquiry into sudden infant death syndrome (SIDS) in 1987 furnished us with detailed epidemiological data for 281 cases that underwent a thorough post-mortem examination. This analysis uses these data to evaluate the role the autopsy plays in explaining sudden death. The cases were classified into three diagnostic groups: explained causes of death (group 1), unexplained deaths with anomalies (group 2), and no anomaly (group 3). These 281 cases show the three essential features that characterize SIDS: over-representation of males, increased deaths during the second and third months of life, and increased deaths during winter. The autopsy examination revealed that many of these deaths had a medical explanation. Almost half were assigned to group 1. At the time of autopsy, no precise pathology could be diagnosed for 147 deaths; of these, 140 showed histological anomalies. There were only seven sudden deaths for which no abnormal sign was evident at the autopsy. These results are compared with those of similar studies and discussed in connection with three factors: the initial selection of cases, the nature and degree of the investigations, and the possible interpretations of the symptoms uncovered.     

Promoting vital involvement

Health care for the elderly generally focuses on health problems. This approach ignores the strengths and resources that maximize a person's autonomy, integrity, and ability to make contributions to society; and it exacerbates poor health. Vital involvement practice (VIP) is an approach to caring for the elderly that emphasizes an individual's capabilities by exploring factors both internal and external to the individual. VIP is identified as a model for health care providers that will improve the health and quality of life of elderly patients.     

Hyperalgesia and blunted morphine analgesia in G protein-gated potassium channel subunit knockout mice

Our aim was to determine whether G protein-gated potassium (Kir3) channels contribute to thermonociception and morphine analgesia. Western blotting was used to probe for the presence of Kir3.1, Kir3.2, Kir3.3, and Kir3.4 subunits in the mouse brain and spinal cord. Hot-plate paw-lick latencies for wild-type, Kir3.2 knockout, Kir3.3 knockout, and Kir3.4 knockout mice were measured at 52 degrees C and 55 degrees C, following the s.c. injection of either saline or 10 mg/kg morphine. Paw-lick latencies for Kir3.4 knockout mice were similar to those of wild-type mice, consistent with the restricted expression pattern of Kir3.4 subunit in the mouse brain. In contrast, Kir3.2 knockout and Kir3.3 knockout mice displayed hyperalgesia at both temperatures tested, and both Kir3.2 knockout and Kir3.3 knockout mice displayed shorter paw-lick latencies following morphine administration, with Kir3.2 knockout mice exhibiting the more dramatic phenotype. Kir3.2/Kir3.3 double knockout mice displayed a greater degree of hyperalgesia than either the Kir3.2 knockout or Kir3.3 knockout mice, while performing similarly to Kir3.2 knockout mice following morphine administration. We conclude that G protein-gated potassium channels containing Kir3.2 and/or Kir3.3 play a significant role in responses to moderate thermal stimuli. Furthermore, the activation of Kir3 channels containing the Kir3.2 subunit contributes to the analgesia evoked by a moderate dose of morphine. As such, receptor-independent Kir3 channel agonists may represent a novel and selective class of analgesic agent.