UV- and gamma-radiation sensitive mutants of Arabidopsis thaliana

Arabidopsis seedlings repair UV-induced DNA damage via light-dependent and independent pathways. The mechanism of the "dark repair" pathway is still unknown. To determine the number of genes required for dark repair and to investigate the substrate-specificity of this process we isolated mutants with enhanced sensitivity to UV radiation in the absence of photoreactivating light. Seven independently derived UV sensitive mutants were isolated from an EMS-mutagenized population. These fell into six complementation groups, two of which (UVR1 and UVH1) have previously been defined. Four of these mutants are defective in the dark repair of UV-induced pyrimidine [6-4]pyrimidinone dimers. These four mutant lines are sensitive to the growth-inhibitory effects of gamma radiation, suggesting that this repair pathway is also involved in the repair of some type of gamma-induced DNA damage product. The requirement for the coordinate action of several different gene products for effective repair of pyrimidine dimers, as well as the nonspecific nature of the repair activity, is consistent with nucleotide excision repair mechanisms previously described in Saccharomyces cerevisiae and nonplant higher eukaryotes and inconsistent with substrate-specific base excision repair mechanisms found in some bacteria, bacteriophage, and fungi.     

Localization of the gene for thiamine-responsive megaloblastic anemia syndrome, on the long arm of chromosome 1, by homozygosity mapping

Thiamine-responsive megaloblastic anemia, also known as "TRMA" or "Rogers syndrome," is an early-onset autosomal recessive disorder defined by the occurrence of megaloblastic anemia, diabetes mellitus, and sensorineural deafness, responding in varying degrees to thiamine treatment. On the basis of a linkage analysis of affected families of Alaskan and of Italian origin, we found, using homozygosity mapping, that the TRMA-syndrome gene maps to a region on chromosome 1q23.2-23.3 (maximum LOD score of 3.7 for D1S1679). By use of additional consanguineous kindreds of Israeli-Arab origin, the putative disease-gene interval also has been confirmed and narrowed, suggesting genetic homogeneity. Linkage analysis generated the highest combined LOD-score value, 8.1 at a recombination fraction of 0, with marker D1S2799. Haplotype analysis and recombination events narrowed the TRMA locus to a 16-cM region between markers D1S194 and D1S2786. Several heterozygote parents had diabetes mellitus, deafness, or megaloblastic anemia, which raised the possibility that mutations at this locus predispose carriers in general to these manifestations. Characterization of the metabolic defect of TRMA may shed light on the role of thiamine deficiency in such common diseases.     

Trypanosoma cruzi: protective response of vaccinated mice is mediated by CD8+ cells, prevents signs of polyclonal T lymphocyte activation, and allows restoration of a resting immune state after challenge

Currently, there is no vaccine available against Chagas' disease. Immune abnormalities induced by T. cruzi pose particular difficulties for vaccine development, since immunological memory must be able to overcome them to prevent spread of infection/sequelae. We have previously demonstrated that experimental vaccination with live CL-14 trypomastigotes does not induce polyclonal lymphocyte activation, immunosuppression, or pathology and efficiently immunizes against virulent T. cruzi. Herein we show that: (1) expansion of CD4+ and CD8+ subsets peaks 2 weeks after infective challenge in both challenged-vaccinated mice and infected controls, but the former exhibit a smaller increase in blastogenesis and in the numbers of activated CD11a(hi)CD4+ and CD11a(hi)CD8+ cells; (2) in long-term-vaccinated mice, expansion of activated subsets (CD62Llo/- and CD11a(hi)) is accelerated among CD8+ PBL 1 week after challenge; (3) challenged-vaccinated mice retract the CD8+-activated subset 5 weeks after challenge, different from infected controls; (4) protection conferred by CL-14 immunization can be adoptively transferred to na?ve recipients with lymphocyte suspensions, and prior depletion of CD8+ (but not of CD4+) cells abolishes protective immunity. Our findings indicate that protective immunity generated by CL-14 immunization involves a transient CD8+ recall response and is capable of preventing the signs of polyclonal lymphocyte activation induced by virulent challenge.     

The effect of haemolysis on blood glucose meter measurement

A study was performed to assess the effect of varying degrees of sample haemolysis on the measurement of blood glucose by the Accutrend, Companion 2, ExacTech, Glucometer II, Glucometer 4, One Touch II, and Reflolux II blood glucose meters. Fresh venous blood was sonicated to induce complete haemolysis and then added in increasing proportions to homologous untreated blood to obtain nine samples with free haemoglobin concentrations up to 50 g l-1. The Accutrend meter showed the only significant (p < 0.05) linear relationship to degree of haemolysis (r = 0.988, p < 0.0001). For every 7% of red cells lysed, the Accutrend value increased by 15%. All other meters gave results which were within 15% of the non-haemolysed value. However, extreme (100%) haemolysis not only affected the Accutrend (glucose value 108% greater than reference) but also the ExacTech (+98%), the Glucometer II (-32%), and the Companion 2 (-41%). Thus, unwitting use of a haemolysed sample to measure whole blood glucose may, with the Accutrend in particular, lead to erroneous results.     

Effects of a quick-release form of bromocriptine (Ergoset) on fasting and postprandial plasma glucose, insulin, lipid, and lipoprotein concentrations in obese nondiabetic hyperinsulinemic women

OBJECTIVE: To assess the effect on various aspects of carbohydrate and lipid metabolism of administering a quick-release formulation of bromocriptine (Ergoset) to obese, nondiabetic, hyperinsulinemic women. RESEARCH DESIGN AND METHODS: Hourly concentrations of prolactin, glucose, insulin, free fatty acid (FFA), and triglyceride were measured for 24 h before and after approximately 8 weeks of treatment with Ergoset. In addition, fasting lipid and lipoprotein concentrations and the steady-state plasma glucose (SSPG) concentration in response to a continuous infusion of somatostatin, insulin, and glucose were determined before and after Ergoset administration. RESULTS: Circulating prolactin concentrations were dramatically decreased (P < 0.001) following treatment, associated with a significant fall (P < 0.05) in 24-h-long plasma glucose, FFA, and triglyceride concentrations. Neither circulating plasma insulin concentrations nor the ability of insulin to mediate glucose disposal changed with treatment. Finally, fasting total cholesterol fell (P < 0.05) and the ratio of total to HDL cholesterol decreased (P = 0.06) in association with Ergoset treatment. CONCLUSIONS: The fact that significant metabolic improvement was seen in the obese nondiabetic hyperinsulinemic women studied suggests that Ergoset could be of therapeutic benefit in clinical conditions of hyperglycemia and/or dyslipidemia.     

Nursing and the New Deal: we met the challenge

The years of the great depression were marked with unemployment and economic ruin for many people. Americans were left feeling helpless and hopeless. After the 1932 presidential election of Franklin Roosevelt, his administration embarked on a course of government known as the New Deal. Many new and innovative programs were established to create jobs and a sense of hope for the public. This article will examine four programs that were of particular interest to nursing: the Federal Emergency Relief Act, the Civil Works Act, the Works Progress Act, and the Social Security Act. Nurses of the time embraced these programs. They participated in their development and implementation and made a difference in the lives of many desperate Americans.     

Pain from the lumbar zygapophysial joints: a test of two models

One hundred seventy-six consecutive patients with chronic low-back pain and no history of previous lumbar surgery were studied to test the clinical criteria of Fairbank et al. and Helbig and Lee for zygapophysial joint pain. All patients underwent a history, examination, and a series of zygapophysial joint injections or blocks of the medial branches of the dorsal ramus with lignocaine. Those patients responding to the first series of blocks were given confirmatory blocks using bupivacaine. None of the clinical features tested was found to be associated with response to the confirmatory block. The Fairbank et al. and Helbig and Lee criteria were shown to be unreliable in distinguishing pain of zygapophysial joint origin from pain of other origins.     

Glypican 3 and glypican 4 are juxtaposed in Xq26.1

This paper reports the development of a dual column system for the simultaneous separation of fluorescent short-chain ceramide, 6-[(7-nitrobenz-2-oxa-1,3,-diazol-4-yl[NBD])amino]hexanoyl-sphingo sine and its metabolites, C6-NBD-sphingomyelin and C6-NBD-glucosylceramide, as well as the fluorescent derivatives of choline and serine phosphatides. The method enables the separation of these lipids in a single run on the basis of the polarity of their headgroups and hydrophobicity of their acyl backbone. The fluorescent properties of the NBD-label make it possible to quantitate small amounts of NBD-lipid analogues. The sensitivity of the presented method thus permits the use of small sample volumes and the determination of NBD-lipid analogues secreted into mouse bile directly, without prior extraction or concentration steps.     

Postprandial lipid metabolism and beta-cell function in non-insulin-dependent (type 2) diabetes mellitus after a mixed meal with a high fat content

Postprandial lipid profiles and release of insulin (INS), intact proinsulin (PI), and 32-33 split proinsulin (SPI) in response to a mixed meal with a high fat content were determined over a 12 h period in non-obese control subjects (n = 10) and non-insulin-dependent (Type 2) diabetic (NIDDM) patients with normotriglyceridaemia (NTG; n = 11) and hypertriglyceridaemia (HTG; n = 10), by calculation of the 'areas under the curves' (AUC). The postprandial triglyceride-AUC was significantly greater in HTG-NIDDM patients (p < 0.05) than in NTG-NIDDM or control subjects. Chylomicron clearance was impaired only in HTG-NIDDM patients (p < 0.05). Chylomicron-remnant clearance was impaired in both groups of NIDDM patients (p < 0.05). The postprandial suppression of plasma non-esterified fatty acid (NEFA) content was impaired in HTG-NIDDM patients (p < 0.05). The postprandial INS-, PI- and SPI-AUCS were significantly greater than in the control subjects (p < 0.05). In NIDDM, triglyceride-AUC correlated significantly with PI and SPI release (triglyceride-AUC vs PI, p < 0.05; triglyceride-AUC vs SPI, p < 0.01). Chylomicron AUC was unrelated to the fasting plasma INS, PI or SPI content, unlike chylomicron-remnant-AUC (Chylomicron-remnant-AUC vs INS, p = NS; chylomicron-remnant-AUC vs PI, p < 0.01; chylomicron-remnant-AUC vs SPI, p < 0.01). The NEFA response was associated with fasting plasma SPI content (NEFA-AUC vs SPI, p < 0.05). Postprandial chylomicron AUC was not related to the overall secretion of INS, PI or SPI. However, triglyceride-, chylomicron-remnant- and NEFA-AUCs were all associated positively with the release of PI and SPI (p < 0.05). In multivariate analyses, chylomicron-remnant clearance had the major relationship with the release of insulin precursors, accounting for 23% of the variability (p < 0.01). Inclusion of overall response of free fatty acids improved the model, with both parameters together accounting for 30% of the variability (p < 0.01). The output of the beta-cell over the postprandial period differed between the NIDDM patients and the control subjects in that when glycaemic stimulation was moderate, the proportion of insulin-like molecules as a percentage of the total output was greater than in control subjects but this was not the situation when glycaemia was greatest. We conclude that abnormal postprandial lipaemia in NIDDM is associated with beta-cell output, possibly mediated by the availability of free fatty acids.