Measurement of the branching fractions of B-->D**(l) nu(l) decays in events tagged by a fully reconstructed B meson

We report a measurement of the branching fractions of B-->D**(l) nu(l), decays based on 417 fb(-1) of data collected at the Y(4S) resonance with the BABAR detector at the PEP-II e+e- storage rings. Events are selected by full reconstructing one of the B mesons in a hadronic decay mode. A fit to the invariant mass differences m(D(*) pi)- m(D(*)) is performed to extract the signal yields of the different D** states. We observe the B-->D**l(-1)nu(l) decay modes corresponding to the four D states predicted by heavy quark symmetry with a significance greater than 5 standard deviations including systematic uncertainties.

Palmitate induced lipoapoptosis of exocrine pancreas AR42J cells

Chronic surplus of dietary consumption, typical to obesity, results in overflow of fat to non-adipose tissues. Intracellular accumulation of fat in non-adipose tissues is associated with cellular dysfunction and cell death and ultimately contributes to the pathogenesis of chronic diseases. The influence of fat overflow on the exocrine pancreas is not known. The purpose of this research was to study the lipotoxic and lipoapoptotic effect of prolonged (72 h) long chain saturated palmitic fatty acid (0.1 mM) on the survival of exocrine pancreas AR42J cells. We demonstrate that chronic exposure of AR42J cells to palmitic acid results in significant increase in triglycerides accumulation (up to 25% of cells area), compared to untreated cultures. Lipid accumulation prompted a typical apoptotic process, demonstrated by both DNA fragmentation and condensed chromatin appearance (DAPI staining). Quantitative real-time PCR studies demonstrated that prolonged palmitic acid supplementation induced down-regulation of the anti-apoptotic Bcl2 mRNA levels (22%) and up-regulation of the pro-apoptotic Bax mRNA levels (300%), leading to disruption of the pro/anti apoptotic balance (Bax/Bcl2=3). No major change was detected in iNOS mRNA expression. In conclusion, prolonged exposure to saturated palmitic acid induces lipoapoptosis in exocrine pancreatic AR42J cells, through disturbance of the Bax/Bcl-2 balance.

First Report of Root and Collar Rot by Sclerotium rolfsii on Apple Trees in Italy

Sclerotium rolfsii Sacc. (teleomorph Athelia rolfsii (Curzi) Tu & Kimbrough) is a polyphagous, soilborne plant pathogen. In summer 1998, a sudden death of 2-year-old apple trees (Malus domestica Borkh.) cv. Royal Gala grafted on M9 rootstock was observed in an orchard near Rome, Italy. Symptoms were stunted vegetation, leaf chlorosis, and root and collar rot. A fungus identified as S. rolfsii was observed producing sclerotia and whitish mycelial strands on root and collar bark. Isolations from roots and at the margin of subcortical necrosis on the collar consistently yielded S. rolfsii colonies on potato dextrose agar (PDA); sclerotia developed within 7 days. Koch's postulates were fulfilled by inoculating 10 1-year-old apple tree cv. M9 rootstocks, grown in 3.5-liter pots, with an S. rolfsii isolate grown for 1 week on PDA at 25°C. One ground plate per plant was used, placed around collar and main roots. Five control plants were treated with PDA only. Rootstocks were kept in the greenhouse at 26 ± 2°C. Within 2 months, 70% of inoculated plants died, with marked necrosis girdling the collar. The other inoculated plants showed a general decline, with widespread necrosis on collars and main roots. Control plants remained healthy. S. rolfsii was reisolated from collars and roots of symptomatic plants. S. rolfsii has been recorded on apple trees in the U.S., India, China, and Israel. In Italy, it is destructive on several crops, and was recently recorded on walnut (1). This first outbreak of S. rolfsii on apple in Italy may have been favored by exceptionally warm late spring and summer temperatures. Reference: (1) A. Belisario and L. Corazza. Plant Dis. 80:824, 1996.

First Report of Alternaria alternata Causing Leaf Spot on English Walnut

A foliar disease of English walnut (Juglans regia L.) was observed in 1998 in an orchard in northern Italy. Symptoms consisted of circular, necrotic spots bordered with concentric zones of darker tissue. Average lesion diameter was 20 mm, although lesions could extend to half of the leaflet lamina. A fungus identified as Alternaria alternata (Fr.:Fr.) Keissl. (1) was observed on the necrotic tissue and was consistently isolated from the margins of the necrosis. Conidia from leaves were brown, ellipsoid to ovoid (primary conidia 28 to 60 × 8 to 15 μm; secondary conidia 10 to 30 × 7 to 13 μm), with walls often ornamented, 1 to 6 transversely septate and 0 to 3 longitudinally septate. For pathogenicity tests, three isolates were grown on potato dextrose agar for 2 weeks. Inoculations were performed on detached, surface-sterilized, healthy J. regia leaflets. Four drops (5 μl each) of a sterile water suspension of 1 × 10⁵ conidia per ml were placed on each leaflet; three leaves per isolate were used. Leaves were incubated in a moist chamber. After 10 days, leaf spots similar to the original symptoms developed on all the inoculated points for all three isolates, and the pathogen was reisolated. Control leaflets inoculated with sterile, distilled water remained symptomless. The experiment was performed three times and the results were similar. Alternaria alternata is a well-known pathogen on many crops but a few records report this fungus as a causal agent of leaf spot on deciduous trees. This is the first report of A. alternata on English walnut. Reference: (1) E. G. Simmons. Mycotaxon 37:79, 1990.

First Report of Myrothecium verrucaria from Muskmelon Seeds

Myrothecium verrucaria (Albertini & Schwein.) Ditmar:Fr. was isolated from muskmelon (Cucumis melo L.) seeds of Charentais-T, a culti var used as a differential host with no resistance to Fusarium oxysporum f. sp. melonis races. A white floccose mycelial mat developed on melon seeds during incubation on moist blotters. Mycelia were mass transferred from melon seeds onto potato dextrose agar (PDA) medium. At 25°C in the dark, a mycelial mat with characteristic annelations of greenish-black sporodochia, without setae, was produced. Conidia (2 to 3 × 6 to 10 μm) were lemon shaped, with a typical conical mucous appendage at one end, which was visible with Loeffer's flagella stain (1). Based on these characteristics, the fungus was identified as M. verrucaria. For pathogenicity studies, surface sterilized seeds of C. melo cv. Charentais-T were coated with M. verrucaria conidia by gently rubbing the seeds on sporodochia produced on 15-day-old cultures on PDA. Once coated, seeds were plated onto water agar and on sterile moist blotters in 9-cm-diameter petri dishes. Plates were incubated at 28°C in the dark. Five seeds per plate and three plates per experiment were used. Experiments were replicated three times. Control seeds were plated without coating. After 7 days, on water agar, 90% of melon seeds failed to germinate while the remaining 10% produced young seedlings that died from root rot and necrotic lesions on the hypocotyl. After 12 days on moist blotters, 100% of the melon seedlings died, showing necrotic lesions on the hypocotyl and on the main root. The pathogen was reisolated from symptomatic melon seedlings. All control seeds germinated and grew into healthy seedlings. M. verrucaria, known to be a seed-borne pathogen, has been isolated from soil and plants worldwide (2). This is the first report of M. verrucaria pathogen on muskmelon. This fungus is not a serious concern when seeds are dressed with fungicides. References: (1) K. V. A. Thompson and S. C. Simmens. Nature. 193:196, 1962. (2) S.-M. Yang and S. C. Jong. Plant Dis. 79:994, 1995.

Lymphocyte subsets and natural killer cell activity in healthy old people and centenarians

The contribution of the immune system to healthy aging and longevity is still an open question. For this reason, several immune parameters (T, B, and natural killer [NK] cell subsets; non-major histocompatibility complex [MHC]-restricted cytotoxic activities, ie, natural and redirected killing [RDK] activities) were studied in a total of 138 healthy subjects of different ages, from 4 to 106 years of age, including 26 centenarians. The major age-related modifications were the following: (1) a decrease in the absolute number of T lymphocytes (CD3+), involving both CD4+ and CD8+ subsets, accompanied by a marked concomitant increase in the number of activated T cells (CD3+, HLA-DR+); (2) a marked decrease in the number of B lymphocytes (CD19+); and (3) an increase in the number of cells with markers of NK activity and of T lymphocytes able to mediate non-MHC-restricted cytotoxicity. These modifications linearly progressed with age and centenarians followed the trend, suggesting that their immune system did not escape the aging process. However, other immunohematologic parameters (number of red blood cells, platelets, and leukocytes) and important immune functions, such as cytotoxic activities (NK and RDK cell activities), were well preserved throughout life until the last decades of life. Unexpectedly, in apparently healthy middle-aged subjects, a decrease of cytotoxic activities was observed in comparison with those of both young controls and centenarians. In conclusions, our data suggest that in centenarians some immune responses are kept at a high level of efficiency, likely contributing to their successful aging. However, this selected group of people does not escape the aging process, as shown by the progressive derangement of a variety of immune parameters.

Cytofluorimetric identification of two populations of double positive (CD4+,CD8+) T lymphocytes in human peripheral blood

Two different subsets of CD4+,CD8+ T lymphocytes have been identified in peripheral blood collected from normal subjects and from patients with different diseases. The subpopulations differed in the degree of CD4 and CD8 antigen expression. Hence, it was possible to distinguish by cytofluorimetric analysis cells with a low (dim) or with a high (bright) fluorescence intensity after the staining with anti-CD4 or anti-CD8 mAbs. CD4+dim,CD8+bright lymphocytes were found in patients with EBV-infectious mononucleosis and were present for less than a month. CD4+bright,CD8+dim T cells were observed in neoplastic patients as well as in healthy subjects and were continuously present in similar percentages over a long period of time (at the moment, about 3 years). Both the subpopulations expressed CD2, CD3, CD5 antigens and had an alpha beta-TCR, but did not express CD1a or CD7. Only CD4+dim,CD8+bright cells expressed HLA-DR antigen and the activation marker CD38, while only CD4+bright,CD8+dim lymphocytes expressed CD56 and CD57 molecules. The hypothesis may be put forward that these two subsets represent an effort of the immune system to cope with different requirements, i.e., of viral or neoplastic origin, while it is not clear the meaning of these cells in healthy subjects.

Age-related expansion of functionally inefficient cells with markers of natural killer activity in Down's syndrome

Peripheral blood lymphocyte subsets of two groups of patients affected by Down's syndrome (DS), ie, 28 children and nine adults of relatively advanced age (greater than 34 years), were investigated and compared with those of age- and sex-matched healthy controls (13 children and 20 adults). Particular attention was devoted to cells with markers of natural killer (NK) activity. Double- and triple-color cytofluorimetric analysis was used to better characterize the phenotypic features of the different subsets. Apart from a reduced number of T lymphocytes (CD3+) in DS children and of B lymphocytes (CD19+) in both DS groups, the major alteration we found was a marked age-related increase of the percentage of cells bearing markers associated with NK activity, such as CD16, CD56, and CD57. These DS cells were apparently severely defective as far as their function was concerned, because NK activity was significantly reduced in comparison with age-matched controls, but still capable of responding to cytokines such as interleukin-2, interferon-beta, and interferon-gamma, and to the modulation of lytic activity exerted by the anti-CD16 monoclonal antibody. On the whole, our data stress the importance of studying DS subjects of different ages to fully appreciate the immunologic derangement characteristic of this syndrome.