A highly specific L-galactose-1-phosphate phosphatase on the path to ascorbate biosynthesis

Ascorbate is a critical compound in plants and animals. Humans are unable to synthesize ascorbate, and their main source of this essential vitamin are plants. However, the pathway of synthesis in plants is yet to be established, and several unknown enzymes are only postulated to exist. We describe a specific L-galactose-1-phosphate (L-gal-1-P) phosphatase that we partially purified from young kiwifruit (Actinidia deliciosa) berries. The enzyme had a native molecular mass of approximately 65 kDa, was completely dependent on Mg2+ for activity and was very specific in its ability to hydrolyze L-gal-1-P. The activity had a pH optimum of 7.0, a K(-M(L-gal-1-P) of 20-40 microM and a Ka(Mg2+) of 0.2 mM. The activity was inhibited by Mg2+ at concentrations >2 mM. The enzyme from Arabidopsis thaliana shoots showed similar properties to the kiwifruit enzyme. The Arabidopsis thaliana enzyme preparation was digested with trypsin, and proteins present were identified by using liquid chromatography-MS. One of 24 proteins present in our preparation was an Arabidopsis thaliana protein, At3g02870, annotated myo-inositol-1-phosphate phosphatase in GenBank, that matched the characteristics of the purified l-gal-1-phosphate phosphatase. We then expressed a kiwifruit homologue of this gene in Escherichia coli and found that it showed 14-fold higher maximum velocity for l-gal-1-P than myo-inositol-1-P. The expressed enzyme showed very similar properties to the enzyme purified from kiwifruit and Arabidopsis, except that its KM(L-gal-1-P) and Ka(Mg2+) were higher in the expressed enzyme. The data are discussed in terms of the pathway to ascorbate biosynthesis in plants.     

Comparison of Blood Pressure Measured by Oscillometry from the Supraorbital Artery and Invasively from the Radial Artery

In previous studies, oscillometric blood pressure measured from the supraorbital artery has been shown to agree quite well with pressure measured from the brachial artery in normal subjects. In this study, surgical patients whose conditions warranted the use of invasive blood pressure monitoring during the surgery were chosen. We compared systolic and diastolic blood pressure measured oscillometrically from the supraorbital artery with intraarterial blood pressures, measured invasively from the radial artery. A pressure bladder was attached to the forehead of each patient. The bladder was connected to a forehead blood pressure monitor. A catheter was inserted in a radial artery, and connected to a pressure monitor. Forehead blood pressure was measured every 5 min. Radial arterial pressure was averaged over the same period during which the forehead measurement was made. Blood pressures measured with the two methods were compared. For the systolic pressure, the difference between the two methods was –9.9 ± 17.9 mm Hg (mean ± SD). For diastolic pressure, the difference was –8.0 ± 10.9 mm Hg. There was a significant difference between the two methods in the patient population chosen in this study.     

Cytopenia induction by 5-fluorouracil identifies thrombopoietic mutants in sensitized ENU mutagenesis screens

The ability of random mutagenesis techniques to annotate the mammalian genome can be hampered due to genetic redundancy and compensatory pathways that mask heterozygous mutations under homeostatic conditions. The objective of this study was to devise a pharmacologically sensitized screen using the chemotherapeutic drug, 5-fluorouracil (5FU), to induce cytopenia. 5FU dose was optimized in the 129/SvImJ, C57BL/6J, BALB/cJ, and C3H/HeJ strains of laboratory mice. N-ethyl-N-nitrosourea (ENU) mutagenesis was performed on 129/SvImJ males and phenotypic variants were identified by backcrossing on to the C57BL/6J background. G1 animals were challenged with 100 μg/g 5FU and phenodeviants with altered platelet recovery were monitored. Of 546 G1 animals tested, 15 phenodeviants were identified that displayed increased baseline platelet number, a platelet overshoot, or delayed platelet recovery, thereby demonstrating the utility of this approach for uncovering mutations in megakaryocyte and platelet development. Four G1 mice were selected for further analysis. The phenotypes were heritable in all four strains and genetic mapping identified a chromosome location in two of the three G2 lines tested. In conclusion, our group has developed a sensitized random mutagenesis screen utilizing 5FU and has shown that the strain combination of 129/SvImJ × C57BL/6J is robust for identification of founder lines with defects in megakaryocyte and platelet development.     

Telomere length and risk of Parkinson's disease

We investigated whether telomere length was associated with the risk of Parkinson's disease (PD) in a case‐control study (96 cases and 172 age‐matched controls) nested within the Health Professionals Follow‐up Study. Relative ratio of telomere repeat copy number to single‐gene copy number in peripheral blood leukocytes was determined by quantitative real time PCR. Men with shorter telomeres had a lower PD risk (multivariate adjusted relative risk for the lowest vs. the highest quartile 0.33; 95% confidence interval: 0.12–0.90). Our results suggest that, contrary to telomere attrition observed in several aging‐related diseases, shorter telomeres are not associated with an increased risk of PD. © 2007 Movement Disorder Society     

Changes in caudate volume after exposure to atypical neuroleptics in patients with schizophrenia may be sex-dependent

BACKGROUND: Changes in the volume of the caudate nucleus over time in patients with schizophrenia has been shown to be directly related to neuroleptic exposure. Few studies have evaluated caudate volume in subjects with schizophrenia who were neuroleptic naive at intake and treated exclusively with atypical neuroleptics. METHODS: Fourteen patients were matched by gender to 14 healthy controls and were evaluated over time using MRI. The patients were neuroleptic na?ve at intake and at follow-up had been treated exclusively with atypical neuroleptics. Difference scores were calculated for caudate volumes. Neuroleptic exposure was quantified using a dose-years formula. RESULTS: There was no difference between patients and controls in the amount of change over time in the volume of the caudate. However, the female patients had a negative correlation (r= - 0.74) between drug exposure and volume change while the male patients had a positive correlation (r = 0.63). Therefore, there was a significant gender effect on the relationship between atypical neuroleptic exposure and changes in the structure of the caudate over time (test for difference in correlations: z = 2.39, p = 0.016). CONCLUSIONS: The change in caudate nucleus volume over time with exposure to atypical neuroleptics may be sex-dependent. Atypical neuroleptic expsoure was associated with volume increase over time in the males, while exposure in females was associated with volume decrement over time.     

Linking the elements of change: Program and client responses to innovation

The process of innovation adoption was investigated using longitudinal records collected from a statewide network of almost 60 treatment programs over a 2-year period. Program-level measures of innovation adoption were defined by averaged counselor ratings of program training needs and readiness, organizational functioning, quality of a workshop training conference, and adoption indicators at follow-up. Findings showed that staff attitudes about training needs and past experiences are predictive of their subsequent ratings of training quality and progress in adopting innovations a year later. Organizational climate (clarity of mission, cohesion, openness to change) is also related to innovation adoption. In programs that lack an open atmosphere for adopting new ideas, it was found that counselor trial usage is likely to be attenuated. Most important was evidence that innovation adoption based on training for improving treatment engagement was significantly related to client self-reports of improved treatment participation and rapport recorded several months later.     

Sclerosing lymphocytic lobulitis of the breast in a patient with Graves' disease.

A 43-year-old woman presented to the endocrinologist with symptoms and signs of typical thyrotoxicosis caused by Graves' disease. Review of systems revealed that she had recently discovered a lump in her left breast. Evaluation of the left breast lesion led to a core biopsy that showed sclerosing lymphocytic lobulitis. This breast disease, well recognized in the pathology literature, occurs in various autoimmine disorders, particularly type 1 diabetes mellitus, and has occasionally been reported in Hashimoto's thyroiditis. The patient described here represents the first published association of sclerosing lymphocytic lobulitis of the breast with Graves' disease.