Biomedical subjects

George Kannourakis

Publications and source records attributed to George Kannourakis.

4 recordsLinked to original sources

PubMed2006

The incidence of leukemia and mortality from sepsis in patients with severe congenital neutropenia receiving long-term G-CSF therapy.

In patients with severe congenital neutropenia (SCN), sepsis mortality is reduced by treatment with granulocyte colony-stimulating factor (G-CSF), but myelodsyplastic syndrome and acute myeloid leukemia (MDS/AML) have been reported. We studied 374 patients with SCN and 29 patients with Shwachman-Diamond syndrome (SDS) on long-term G-CSF enrolled in the Severe Chronic Neutropenia International Registry. In SCN, sepsis mortality was stable at 0.9% per year. The hazard of MDS/AML increased significantly over time, from 2.9% per year after 6 years to 8.0% per year after 12 years on G-CSF. After 10 years, the cumulative incidence was 8% for sepsis mortality and 21% for MDS/AML. A subgroup of SCN patients (29%) received more than the median dose of G-CSF (> or = 8 microg/kg/d), but achieved less than the median absolute neutrophil count (ANC) response (ANC < 2.188 x 10(9)/L [2188/microL] at 6-18 months). In these less-responsive patients, the cumulative incidence of adverse events was highest: after 10 years, 40% developed MDS/AML and 14% died of sepsis, compared with 11% and 4%, respectively, of more responsive patients whose ANC was above the median on doses of G-CSF below the median. Risk of MDS/AML may be similar in SDS and SCN. In less-responsive SCN patients, early hematopoietic stem cell transplantation may be a rational option.

Female↗

PubMed2003

Severe chronic neutropenia: treatment and follow-up of patients in the Severe Chronic Neutropenia International Registry.

Severe chronic neutropenia (SCN) is defined as an absolute neutrophil (ANC) of less than 0.5 x 10(9)/L, lasting for months or years. Congenital, cyclic, and idiopathic neutropenia are principal categories of SCN. Since 1994, the Severe Chronic Neutropenia International Registry (SCNIR) has collected data to monitor the clinical course, treatments, and disease outcomes for SCN patients. This report summarizes data for 853 patients, almost all treated with daily or alternate-day recombinant human granulocyte colony-stimulating factor (G-CSF or Filgrastim). G-CSF treatment increased the ANC overall from 0.34 x 10(9)/L +/- 0.018 pre-treatment to 3.70 x 10(9)/L +/- 0.18 during the first year of treatment. For most patients, the responses were durable with patients remaining on the same dose of G-CSF for many years. Long-term hematological observations showed stable mean leukocyte and neutrophil counts and gradually increasing hemoglobin levels. Thrombocytopenia developed in 4% of patients. As of January 1, 2000, myelodysplasia (MDS) or acute myelogenous leukemia (AML) has occurred in 35 of 387 patients with congenital neutropenia with a cumulative risk of 13% after 8 years of G-CSF treatment. This event occurred without a predictable relationship to the duration or dose of G-CSF treatment. No patients with cyclic or idiopathic neutropenia developed MDS or AML. Other important adverse events included hepatomegaly, osteoporosis, vasculitis, glomerulonephritis, and deaths in 4 of 14 cases requiring splenectomy. Growth and development and the outcome of pregnancy appeared to be unaffected by G-CSF treatment. These data indicate that congenital, cyclic, and idiopathic neutropenia can be effectively treated with long-term G-CSF. The risk of leukemia, osteoporosis, other potentially adverse events, and pregnancy outcome need to be further evaluated with continuing long-term observations.

Adolescent↗

PubMed2002

Glycogen storage disease.

Glycogen storage disease (GSD) is a rare autosomal-recessive disorder characterized by hypoglycemia, hepatosplenomegaly, seizures, and failure to thrive in infants. Neutropenia and/or neutrophil dysfunction develops in GSD1b, but not in other types. GSD1b results from a deficiency of the glucose-6-phosphate translocase enzyme and the genetic defect maps to chromosome 11q23. Patients with GSD1b are susceptible to recurrent bacterial infections, commonly involving the perirectal area, ears, skin, and urinary tract, although life-threatening infections, such as septicemia, pneumonia, and meningitis occur less frequently. Although the exact mechanism of neutropenia in patients with GSD1b is not known, treatment with recombinant human granulocyte colony-stimulating factor (G-CSF) has reduced the incidence of infections and has improved the quality of life of these patients. Defects in neutrophil chemotaxis and intracellular bacterial killing have been described and appear to be corrected by the use of G-CSF. To date, no cases of myelodysplasia or acute myeloid leukemia have been observed in patients with GSD1b treated with G-CSF. A significant complication of cytokine therapy is the development of hypersplenism, requiring either a reduction in the dosage of G-CSF or splenectomy.

Bacterial Infections↗

PubMed2002

A time to kill: viral manipulation of the cell death program.

Many viruses have as part of their arsenal the ability to modulate the apoptotic pathways of the host. It is counter-intuitive that such simple organisms would be efficient at regulating this the most crucial pathway within the host, given the relative complexity of the host cells. Yet, viruses have the potential to initiate or stay the onset of programmed cell death through the manipulation of a variety of key apoptotic proteins. It is the intention of this review to provide an overview of viral gene products that are able to promote or inhibit apoptotic death of the host cell and to discuss their mechanisms of action. It is not until recently that the depth at which viruses exploit the apoptotic pathways of their host has been seen. This understanding may provide a great opportunity for future therapeutic ventures.

Animals↗