Enhanced (+)-catechin transglucosylating activity of Streptococcus mutans GS-5 glucosyltransferase-D due to fructose removal.

The (+)-catechin transglucosylating activities of several glucosyltransferases (GTFs) from the genus Streptococcus were compared. For this purpose, a mixture of four GTFs from Streptococcus sobrinus SL-1 and recombinant GTF-B and GTF-D from Streptococcus mutans GS-5 expressed in Escherichia coli were studied. It was shown that after removal of alpha-glucosidase activity, GTF-D transglucosylated catechin with the highest efficiency. A maximal yield (expressed as the ratio of moles of glucoside formed to moles of catechin initially added) of 90% was observed with 10 mM catechin and 100 mM sucrose (K(m), 13 mM) in 125 mM potassium phosphate, pH 6.0, at 37 degrees C. (1)H and (13)C nuclear magnetic resonance spectroscopy revealed the structures of two catechin glucosides, (+)-catechin-4'-O-alpha-D-glucopyranoside and (+)-catechin-4',7-O-alpha-di-D-glucopyranoside. Fructose accumulation during glucosyl transfer from sucrose to the acceptor competitively inhibited catechin transglucosylation (K(i), 9.3 mM), whereas glucose did not inhibit catechin transglucosylation. The addition of yeasts was studied in order to minimize fructose inhibition by means of fructose removal. For this purpose, the yeasts Pichia pastoris and the mutant Saccharomyces cerevisiae T2-3D were selected because of their inabilities to utilize sucrose. Addition of P. pastoris or S. cerevisiae T2-3D to the standard reaction mixture resulted in a twofold increase in the duration of the maximum GTF-D transglucosylation rate. The addition of the yeasts also stimulated sucrose utilization by GTF-D.

Emotional adjustment of children and adolescents with haemophilia in relation to the HIV threat.

A Dutch nation-wide study on young haemophilia patients, whose former treatment placed them at risk for HIV infection, was done to examine the effect of HIV testing, HIV status, disclosure of HIV status and the child's experiences with disease-related information on emotional adjustment. In the Netherlands HIV tests are not routinely performed for paediatric haemophilia patients, but the number of HIV-infected children is estimated to be low (8%). Seventy-two boys with haemophilia, five HIV positive, 51 HIV negative and 16 not tested, and their mothers were interviewed and administered standardized questionnaires. Multiple regression analyses showed no differences in anxiety and depression between HIV-positive, HIV-negative or untested boys, nor between children who were informed or not informed about their HIV status. Conversely, children who experienced more difficulties to obtain information about the their disease were significantly more anxious and tended to be more depressed. No significant differences in emotional distress were found between the patients and a standardization sample of healthy peers. The data provide evidence that children and adolescents with haemophilia cope effectively with their disease and the emotional impact of the HIV threat. There seems to be no reason to protect children from testing or knowing their HIV status. In the absence of compelling medical reasons, however, health care workers should not forcefully advocate testing or early disclosure. Distinct disease and treatment-related factors as well as social factors modify disclosure practices.

Information about diagnosis and prognosis related to anxiety and depression in children with cancer aged 8-16 years.

The aim of this study was to test the hypothesis that being openly informed about the diagnosis and prognosis benefits the emotional well-being of children with cancer. A stratified sample of 56 children with cancer aged 8-16 years and their parents participated. The parents were interviewed about the information they had given to their child. Self-report questionnaires were administered to the children measuring anxiety and depression. Children who received open information about their diagnosis and prognosis at the initial stage of the disease showed significantly less anxiety and depression. Our findings suggest that parents should be advised to inform their child with cancer openly and soon after the initial diagnosis. Physicians should offer help to the parents in dealing with the difficult task of confronting the child with the diagnosis, prognosis and treatment.

Association of 1800 cGy cranial irradiation with intellectual function in children with acute lymphoblastic leukaemia. ISPACC. International Study Group on Psychosocial Aspects of Childhood Cancer.

Cranial radiation therapy in childhood acute lymphoblastic leukaemia has been associated with adverse neuropsychological effects, such as low intelligence. However, records show that these associations usually occur when the dose of radiation used is 2400 cGy. We investigated whether a lower dose of 1800 cGy had the same adverse effects on long-term survivors and whether high doses of methotrexate but no radiation therapy would have a more beneficial effect. We evaluated 203 children for six years in a multi-centre European study. The patients were divided into two groups: 129 children treated with 1800 cGy of cranial radiation therapy and 74 children who received high-dose methotrexate but no radiation therapy. We used full scale intelligence quotient, verbal, and performance IQ tests to assess the patient's intelligence. We found a significant decline in full scale intelligence quotient in the irradiated group that increased with the length of time from diagnosis. Younger age at diagnosis was associated with lower full scale intelligence quotient in the radiated group. Our results indicate that a radiation dose of 1800 cGy can have negative effects on neurocognitive function and we continue to question the benefit of low-dose cranial radiation therapy.

Rat liver microsomal metabolism of 2-halogenated 4-methylanilines.

1. Rat liver microsomal metabolism of 2-fluoro-, 2-chloro- and 2-bromo-4-methylaniline was investigated using h.p.l.c. Metabolites identified include products from side-chain C-hydroxylation (benzyl alcohols and benzaldehydes) and N-hydroxylation (hydroxylamines and nitroso derivatives). Aromatic ring hydroxylation was not a major reaction pathway. 2. A new type of microsomal metabolite was detected which was identified as a secondary amine, i.e. a halogenated N-(4'-aminobenzyl)-4-methylaniline. 3. In addition to these products azoxy, azo and hydrazo derivatives were formed. 4. Benzyl alcohols and halogenated N-(4'-aminobenzyl)-4-methylanilines were the major microsomal metabolites for all three 2-halogenated 4-methylanilines. 5. Quantification of the metabolite patterns demonstrated an influence of the type of halogen substituent on the rate of microsomal metabolism. The rate of side-chain C-hydroxylation increases in the order 2-fluoro-4-methylaniline < 2-chloro-4-methylaniline < 2-bromo-4-methylaniline. 6. The rate of N-hydroxylation increases from 2-bromo-4-methylaniline < 2-fluoro-4-methylaniline < 2-chloro-4-methylaniline. That 2-chloro-4-methylaniline is N-hydroxylated to a larger extent is in accordance with its greater mutagenicity, twice that of 2-bromo-4-methylaniline.

The use of pig hepatocytes to study the biotransformation of beta-nortestosterone by pigs. Identification of glucuronidated 15 alpha-hydroxy-norandrostenedione as an important in vitro and in vivo metabolite.

Porcine hepatocytes were used to examine the biotransformation of beta-nortestosterone (NOR). Initially, the major metabolite of NOR was norandrostenedione (NA), which upon prolonged incubation was further transformed, primarily to the glucuronide of 15 alpha-hydroxy-norandrostenedione (15 alpha OH-NA). No differences were observed in this pattern between hepatocytes isolated from livers of sows or castrated male pigs. With increasing culture age, the rate of formation of NA did not change, contrary to a decrease in its further oxidation and glucuronidation. 15 alpha-OH-NA, primarily as its glucuronide, was identified in the urine of pigs injected with NOR. In addition, NA and the glucuronide of the parent compound were present in much smaller amounts.

Re-examination of cellular cyclic beta-1,2-glucans of Rhizobiaceae: distribution of ring sizes and degrees of glycerol-1-phosphate substitution.

Gel-filtration and thin layer chromatography of low molecular weight carbohydrates from culture filtrates of Agrobacterium radiobacter, Isolate II, have shown, that next to the neutral beta-1,2-glucan fraction a major acidic fraction was present which was found to be glycerophosphorylated cyclic beta-1,2-glucans. Re-examination of cyclic beta-1,2-glucan preparations which had been obtained by extraction of Rhizobium cells with hot phenol-water also showed these acidic modified beta-1,2-glucans to be present. Cyclic beta-1,2-glucans from R. leguminosarum (9 strains) and of R. phaseoli (1 strain) had ring size distribution with degrees of polymerisation (DPs) of 19 and 20 as major ring sizes of which a minor part was glycerophosphorylated; beta-1,2-glucans of R. trifolii (3 strains) had ring sizes with DPs measuring 19-22 as prominent components which were largely unsubstituted, and R. meliloti (7 strains) had beta-1,2-glucans with ring size distributions extending to still higher DPs of 19-25 of which the major part appeared to be glycerophosphorylated.

Aquilide A, a new mutagenic compound isolated from bracken fern (Pteridium aquilinum (L.) Kuhn).

A mutagenic compound, designated aquilide A, was isolated and identified from bracken fern (Pteridium aquilinum (L.) Kuhn). Aquilide A was found to be responsible for greater than 50% of the mutagenic activity observed after incubation of the methanol extract at alkaline conditions. This compound was found to be a potent genotoxic compound in mammalian cells in vitro and therefore, may be responsible for at least part of the carcinogenic activity of bracken. The instability of aquilide A under conditions normally encountered during analytical chemical procedures may explain why so many efforts to elucidate the carcinogenic factor(s) present in bracken have been unsuccessful.

[Intelligence and concentration capacity in children with leukemia and their adaptation to school]. / Intelligentie en concentratiievermogen van kinderen met leukemie en hun aan-passing op school.

In this study we test the hypothesis that children, suffering from acute lymphatic leukaemia (ALL) have more concentration problems, a lower intellectual capacity and more adjustment problems at school. The study deals only with those children whose ALL had been diagnosed at least three years before. Standardized tests have been given to fourteen children (aged 6-12), being treated or checked by the Children's Oncology Center of Amsterdam. Teachers were given a questionnaire and a written interview. Parents were interviewed orally. Scores on tests and questionnaire were compared with scores from norm groups. The study's most important results are: these children with ALL have a low concentration capacity, some adjustment problems at school (withdrawn behavior), but intellectually they don't function at a lower level.