Development of Attention and Accuracy in Learning a Categorization Task.

Being able to categorize objects as similar or different is an essential skill. An important aspect of learning to categorize is learning to attend to relevant features (i.e.

Metabolism of β-valine via a CoA-dependent ammonia lyase pathway.

Pseudomonas species strain SBV1 can rapidly grow on medium containing β-valine as a sole nitrogen source. The tertiary amine feature of β-valine prevents direct deamination reactions catalyzed by aminotransferases, amino acid dehydrogenases, and amino acid oxidases. However, lyase- or aminomutase-mediated conversions would be possible.

A Pseudomonas putida strain genetically engineered for 1,2,3-trichloropropane bioremediation.

1,2,3-Trichloropropane (TCP) is a toxic compound that is recalcitrant to biodegradation in the environment. Attempts to isolate TCP-degrading organisms using enrichment cultivation have failed. A potential biodegradation pathway starts with hydrolytic dehalogenation to 2,3-dichloro-1-propanol (DCP), followed by oxidative metabolism.

Mumps outbreak in a highly vaccinated student population, The Netherlands, 2004.

In September 2004 a mumps outbreak occurred at an international hotel school in The Netherlands. We investigated this outbreak to identify risk factors for mumps. There were 105 mumps cases (overall mumps attack rate (AR) 12% (95% CI: 10-15%)).

One pot 'click' reactions: tandem enantioselective biocatalytic epoxide ring opening and [3+2] azide alkyne cycloaddition.

Halohydrin dehalogenase (HheC) can perform enantioselective azidolysis of aromatic epoxides to 1,2-azido alcohols which are subsequently ligated to alkynes producing chiral hydroxy triazoles in a one-pot procedure with excellent enantiomeric excess.

Dynamic kinetic resolution of racemic beta-haloalcohols: direct access to enantioenriched epoxides.

The direct chemo-enzymatic DKR of racemic beta-haloalcohols is reported, yielding the corresponding optically active epoxides in a single step. The mutant haloalcohol dehalogenase HheC Cys153Ser Trp249Phe is used for the asymmetric ring closure, whereas racemization of the remaining enantiomer of the haloalcohol is achieved using the new iridacycle 3, one of the most effective racemization catalysts to date for beta-haloalcohols.

Selective deletion of antigen-specific, activated T cells by a humanized MAB to CD2 (MEDI-507) is mediated by NK cells.

CD2 is a 50-kDa transmembrane glycoprotein that plays an important role in T and natural killer (NT) lymphocyte functions. CD2 serves as both an adhesion molecule and as a costimulatory molecule through interactions with its ligand, CD58, on antigen presenting or target cells. Consistent with earlier studies using a rat anti-CD2 mAb, we have shown that treatment of alloantigen stimulated T lymphocytes with a humanized mAb, MEDI-507 (IgG1, kappa), induced hyporesponsiveness to subsequent stimulation with alloantigen but not to mitogen (phytohemagglutinin).

Home treatment and reimbursement in The Netherlands.

In The Netherlands home care is one of the most rapidly growing fields in health. It is thought to provide a cheaper alternative to hospitalization and improved quality of life for the patient. However, there is evidence that home care may result in better care but does not reduce the burden on hospital services.

bcl-x, a bcl-2-related gene that functions as a dominant regulator of apoptotic cell death.

We report the isolation of bcl-x, a bcl-2-related gene that can function as a bcl-2-independent regulator of programmed cell death (apoptosis). Alternative splicing results in two distinct bcl-x mRNAs. The protein product of the larger mRNA, bcl-xL, is similar in size and predicted structure to Bcl-2.

Excision products of TCR V alpha recombination contain in-frame rearrangements: evidence for continued V(D)J recombination in TCR+ thymocytes.

Cortical thymocytes that express a TCR on their surface continue to express mRNA for the recombination activating genes RAG-1 and RAG-2. As the expression of these genes appears to be necessary and sufficient for V(D)J recombination to occur, this finding suggests that productive TCR gene rearrangement may not by itself terminate TCR recombination. To further study this question, we have utilized a polymerase chain reaction-based strategy to isolate and sequence excision products of secondary TCR alpha gene rearrangement events.

The HIV epidemic and its effect on the tuberculosis situation in The Netherlands.

To determine the influence of the HIV (human immunodeficiency virus) epidemic on the tuberculosis situation in the Netherlands, we made a retrospective analysis of all reported tuberculosis cases from 1984 through 1990. We studied the course of the tuberculosis incidence in the Netherlands among the group at highest risk for HIV infection (Dutch males, 25-49 years of age, in Amsterdam). This was compared with the course among same-age Dutch males in areas with lower risk for HIV infection and among other-age Dutch males in Amsterdam.

[An outbreak of mostly extrapulmonary tuberculosis in a family practice].

An outbreak of mainly extrapulmonary tuberculosis (TB) in a group of about 550 patients with rheumatoid arthritis (RA) is described. These patients had been attending the practice of a former general practitioner who treated cases of rheumatoid arthritis with phenylbutazone and steroids. The number of diagnosed TB cases was 55.

Chicken T-cell receptor beta-chain diversity: an evolutionarily conserved D beta-encoded glycine turn within the hypervariable CDR3 domain.

Unlike mammals, chickens generate an immunoglobulin (Ig) repertoire by a developmentally regulated process of intrachromosomal gene conversion, which results in nucleotide substitutions throughout the variable regions of the Ig heavy- and light-chain genes. In contrast to chicken Ig genes, we show in this report that diversity of the rearranged chicken T-cell receptor (TCR) beta-chain gene is generated by junctional heterogeneity, as observed in rearranged mammalian TCR genes. This junctional diversity increases during chicken development as a result of an increasing base-pair addition at the V beta-D beta and D beta-J beta joints (where V, D, and J are the variable, diversity, and joining gene segments).

[Sexually transmissible disorders in allochtonous population groups; a pilot study].

In the registration of sexually transmitted diseases (STD) carried out by the nursing staff in the STD clinics the share of the immigrant populations of Turkish, Moroccan, Surinam and Antilles origin was investigated for the period 1986-89. In the total population of STD patients the immigrants appear to be overrepresented. Their share has increased from one-eight to one-fifth of the total number of STD cases.

[Prognosis concerning HIV-infection and AIDS epidemic in The Netherlands based on mathematical analysis].

In the Netherlands by the 1st of January 1990 1074 AIDS patients have been reported to the Department of the Chief Medical Officer. In the last few years the proportion of intravenous drug users increased and the proportion of homo/bisexual men decreased. After adjustment for the effect of delay in reporting the total number of AIDS patients by 1st January 1990 is estimated to be 1173.

[Reported patients with infectious diseases in 1989].

The number of cases of infectious diseases notified in 1989 in accordance with the Infectious Diseases Control and Disease Cause Act are given. Of each A, B and C disease the numbers ar mentioned separately. The most significant changes as compared with the previous years are discussed.

Templated insertions in the rearranged chicken IgL V gene segment arise by intrachromosomal gene conversion.

Chickens create a repertoire for their immunoglobulin light-chain gene by a novel process of sequence substitution within a unique rearranged V gene segment (VL1) during B-cell development in the bursa of Fabricius. Sequence analysis has shown that these nucleotide substitutions are not random. Potential donors for observed sequence substitutions are present within the 25 psi VL segments located 5' of the VL1 gene.