The novel BMI-1 inhibitor PTC596 downregulates MCL-1 and induces p53-independent mitochondrial apoptosis in acute myeloid leukemia progenitor cells.

Disease recurrence is the major problem in the treatment of acute myeloid leukemia (AML). Relapse is driven by leukemia stem cells, a chemoresistant subpopulation capable of re-establishing disease. Patients with p53 mutant AML are at an extremely high risk of relapse. B-cell-specific Moloney murine leukemia virus integration site 1 (BMI-1) is required for the self-renewal and maintenance of AML stem cells. Here we studied the effects of a novel small molecule inhibitor of BMI-1, PTC596, in AML cells. Treatment with PTC596 reduced MCL-1 expression and triggered several molecular events consistent with induction of mitochondrial apoptosis: loss of mitochondrial membrane potential, BAX conformational change, caspase-3 cleavage and phosphatidylserine externalization. PTC596 induced apoptosis in a p53-independent manner. PTC596 induced apoptosis along with the reduction of MCL-1 and phosphorylated AKT in patient-derived CD34+CD38low/- stem/progenitor cells. Mouse xenograft models demonstrated in vivo anti-leukemia activity of PTC596, which inhibited leukemia cell growth in vivo while sparing normal hematopoietic cells. Our results indicate that PTC596 deserves further evaluation in clinical trials for refractory or relapsed AML patients, especially for those with unfavorable complex karyotype or therapy-related AML that are frequently associated with p53 mutations.

Biotypes and serotypes of Haemophilus influenzae ocular isolates.

AIM: To determine which subtypes of Haemophilus influenzae are most commonly associated with ocular disease, and whether the site of ocular H influenzae infection is correlated with specific subtypes of the organism. METHODS: The biotypes and serotypes of ocular H influenzae isolates collected at the Francis I Proctor Foundation between March 1989 and January 2000 were examined. A total of 62 ocular isolates were retrieved from frozen storage and plated on chocolate agar. Biotypes were assigned based upon the ability of the isolates to produce indole, urease, and ornithine decarboxylase. Capsular subtypes a-f were determined by slide agglutination using commercially available subtype specific antisera. Identified biotypes and serotypes were then analysed with regard to site of infection. RESULTS: Patient age ranged from 1 to 92 years with a median age of 45 years. 38 (61%) of the isolates were biotype II, 23 (37%) were biotype III, and one (2%) was biotype VII. All of the isolates were non-encapsulated and thus serologically non-typable. H influenzae biotype II was found in 28 of 48 (58%) conjunctivitis cases, five of eight (63%) keratitis cases, and two of two (100%) endophthalmitis cases. Biotype III was found in 20 of 48 (42%) conjunctivitis cases, two of eight (25%) keratitis cases, and a single case of dacryocystitis. Biotype VII was associated with one of eight (13%) keratitis cases. CONCLUSION: Most ocular H influenzae isolates appear to be serologically non-typable strains from biotypes II and III, less virulent subtypes that frequently colonise the nasopharynx. In addition, the site of ocular H influenzae infections appears to be largely independent of species subtype.

Brain biopsy in primary angiitis of the central nervous system.

To determine the yield of brain biopsy and the predictive value of clinical features and ancillary studies, we retrospectively analyzed hospital chart data from 61 consecutive patients suspected of having primary angiitis of the CNS (PACNS). Biopsies disclosed PACNS in 22 (36%), alternative diagnoses in 24 (39%), and no diagnosis in 15 (25%). Clinical indicators and angiography were not useful predictors of PACNS. Brain biopsy should be the primary diagnostic tool in this setting because of the poor reliability of other indicators and because of the high yield of alternative diagnoses requiring different management.

Genetic analysis of California mastitis test records. II. Score for resistance to elevated tests.

A lactation score for rating individual cows for their apparent resistance to elevation of California Mastitis test is described. The score uses the first nine monthly California Mastitis Tests weighted by the number and position of elevated coded tests. California mastitis test readings of negative and trace were coded "normal" and 1, 2, or 3 "elevated". A cumulative lactation score of 21 was assigned to lactations without elevation in coded test, and a score of zero was assigned to lactations with all nine tests elevated. The number and position of the elevated coded tests influenced the 305-day milk yield, and the position of elevated coded tests influenced lactation persistency. Differences were significant among sire progeny groups for the cumulative lactation score. Heritabilities for the cumulative lactation score were .48 +/- .07, .36 +/- .08, .46 +/- .15, and .23 +/- .12 for first, second, third, and fourth or later lactation groups. Selection for a high cumulative lactation score should reduce the occurrence of elevated coded test scores. The genetic correlation between 305-day milk yield and cumulative score was -.31 +/- .13 for first lactation records.

Genetic analysis of California mastitis test records. I. Coded tests.

A sample of 15,965 Holstein lactation records having California Mastitis Test scores for at least the first 9 mo of standard Dairy Herd Improvement production testing were studied for the effects of sire, parity, and year and month of calving. California Mastitis Test readings of "negative" or "trace" were coded normal while readings of "1", "2", or "3" were coded elevated. The frequency of elevated tests increased as parity increased. Effect of year of calving and a trend toward higher percentages of elevated coded test scores was significant. There was no distinct trend in elevated coded test score with month of calving. Sire effect on the incidence of elevation in the coded score was important. Heritability of first and second lactation monthly coded California Mastitis Test scores from a paternal half-sister analysis within herd, year, and season, for sires with at least 25 daughters ranged from .11 +/- .04 to .48 +/- .07. Genetic correlations between the third test and following tests of first and second lactations ranged from .25 +/-.15 to .58 +/- .18.