Intensive diabetes management decreases Na-Li countertransport in young subjects with type 1 diabetes and enlarged kidneys

In type 1 diabetes, increases in sodium-lithium countertransport (Na-Li CT), kidney volume (KV), and albumin excretion rate (AER) may precede the development of persistent microalbuminuria. Limited data exist on reversibility of these factors early in the evolution of diabetic nephropathy. A crossover design was used to study the separate effects of enalapril and intensive diabetes management (IDM) on Na-Li CT, KV and AER in 17 children and adolescents with type 1 diabetes (5-10 years duration) with large kidneys (>275 ml/1. 73 m(2)) and predominantly normoalbuminuria. Subjects were randomized to receive 3 months of either enalapril (0.25 mg/kg/day) or IDM, a 3-month washout, followed by the alternate treatment for 3 months. During IDM, HbA1c decreased 2.5% (pre 9.5+/-0.3% (mean+/-SE), post 7.0+/-0.1%, p<0.0001), but was unchanged while on enalapril (pre 8.8+/-0.3%, post 8.5+/-0.3%, p=0.1). A significant decrease in Na-Li CT was seen with IDM (pre 0.43+/-0.05, post 0.36+/-0.04 mmol/l RBC/h, p=0.006) but not angiotensin converting enzyme inhibition (ACE-i) (pre 0.39+/-0.04, post 0.38+/-0.04 mmol/RBC/h, p=0.4). Neither ACE-i nor IDM affected KV or AER. It is concerning that kidney enlargement does not appear reversible at this early stage in the pathogenesis of diabetic nephropathy, although our conclusions are limited by the short duration of intervention and small sample size. The reduction in Na-Li CT with IDM suggests this may be a potentially modifiable risk factor for diabetic nephropathy.

Intensive diabetes management in adolescents with type 1 diabetes: the importance of intensive follow-up

Minimal information exists on the education and follow-up required to successfully initiate intensive diabetes management (IDM) in adolescents with type 1 diabetes. We performed a retrospective analysis of HbA1c 3 and 15 months after initiation of IDM in two cohorts: (1) 17 patients who received individualised education in IDM and intensive early follow-up, and (2) 11 patients who participated in group education for initiation of IDM with standard follow-up. Entry HbA1c was higher in the individualised education patients (9.5 +/- 0.3% [mean +/- SE] versus 8.2 +/- 0.4%, p = 0.02). After 3 months of IDM, HbA1c improved in both cohorts reaching similar levels (individualised: 7.0 +/- 0.1%, p < 0.0001 vs entry; group: 7.3 +/- 0.2%, p = 0.05). During the following year, with routine follow-up for both cohorts, HbA1c levels rose approximately 1% as patients reverted to a multiple daily injection regimen. Irrespective of the educational approach, we believe maintenance of IDM and optimal HbA1c requires long-term intensive follow-up.

Systematic reverse genetics of transfer-DNA-tagged lines of Arabidopsis. Isolation of mutations in the cytochrome p450 gene superfamily

We have developed an efficient reverse-genetics protocol that uses expedient pooling and hybridization strategies to identify individual transfer-DNA insertion lines from a collection of 6000 independently transformed lines in as few as 36 polymerase chain reactions. We have used this protocol to systematically isolate Arabidopsis lines containing insertional mutations in individual cytochrome P450 genes. In higher plants P450 genes encode enzymes that perform an exceptionally wide range of functions, including the biosynthesis of primary metabolites necessary for normal growth and development, the biosynthesis of secondary products, and the catabolism of xenobiotics. Despite their importance, progress in assigning enzymatic function to individual P450 gene products has been slow. Here we report the isolation of the first 12 such lines, including one (CYP83B1-1) that displays a runt phenotype (small plants with hooked leaves), and three insertions in abundantly expressed genes. The DNAs used in this study are publicly available and can be used to systematically isolate mutants in Arabidopsis.

GHB: a home brew

Gamma-hydroxybutyric acid is an allegedly benign illicit substance that is gaining increasing recognition and attention among substance abusers and athletes. Alongside foreign-made brands, the compound is also easily available, at low cost because of the facility with which it can be produced in one's kitchen. Named by some "Nature's Quaalude" or sold as a health product, it is often used with a false sense of security as it may cause serious and disabling complications, as illustrated by this clinical vignette.

Giant pseudoaneurysm of the extracranial vertebral artery: case report

Pseudoaneurysms of the extracranial vertebral artery are extremely rare due to their deep location and the anatomical protection of this artery. They can be caused by cervical traumas (firearm injuries, sports, hyperextension of the neck and iatrogeny). The authors report the case of a patient who developed a giant pseudoaneurysm of the extracranial vertebral artery after surgery for the removal of a tumor of the cerebellopontine angle in which surgical lesion of the artery occurred. Treatment was performed by endovascular approach. Literature is reviewed and comments are made on the physiopathogeny of the lesion and the different forms of treatment.

Cloning of wound-induced cytochrome P450 monooxygenases expressed in pea

Cytochrome P450 monooxygenases (P450s) mediate a wide range of oxidative reactions involved in the biosynthesis of plant secondary metabolites including phenylpropanoids and phytoalexins. To investigate the regulation of these P450s in the phenylpropanoid biosynthetic pathway of pea (Pisum sativum), partial cDNAs representing four distinct P450s expressed in pea seedlings were cloned using a reverse transcription-polymerase chain reaction strategy. One of the corresponding full-length cDNA clones, designated CYP73A9, encodes pea trans-cinnamic acid 4-hydroxylase, which catalyzes the second core reaction in the phenylpropanoid pathway. As expected from its central role in the production of lignin precursors and defense compounds, northern analysis of poly(A)+ mRNA demonstrates that transcripts encoding CYP73A9 are induced appreciably within 3 h after wounding. A second cDNA clone, designated CYP82, encodes a novel P450, whose transcripts are also induced in response to wounding at approximately the same time as CYP73A9 transcripts. Despite the multitude of environmental stimuli known to induce expression of phenylpropanoid pathway enzymes, genomic DNA Southern analysis indicates that each of these P450s is encoded by a low copy number (possibly a single copy) gene family.

Involvement of cytochrome P450 in host-plant utilization by Sonoran Desert Drosophila

The four Drosophila species endemic to the Sonoran Desert (Drosophila mettleri, Drosophila mojavensis, Drosophila nigrospiracula, and Drosophila pachea) utilize necrotic cactus tissue or soil soaked by rot exudate as breeding substrates. Each Drosophila species uses a different cactus species as its primary host. D. pachea is limited to senita cactus by a biochemical dependency on unusual sterols available only in that cactus. For the other Drosophila species, no such chemical dependencies exist to explain the relationships with their primary host plants. Each cactus species has a different array of allelochemicals that have detrimental effects on non-resident fly species. We have hypothesized that the desert fly-cactus associations are due, in part, to differences between the fly species in their allelochemical detoxication enzymes, the cytochrome P450 system. To test whether P450s are involved in the detoxication of cactus allelochemicals, several experiments were done. (i) The effect of a specific P450 inhibitor, piperonyl butoxide, on larval survival through eclosion on each cactus substrate was investigated. (ii) In vitro metabolism of cactus alkaloids was determined for each Drosophila species. The effects of specific inducers and inhibitors were included in these experiments. (iii) The basal and induced content of cytochrome P450 in each species was determined. The results support the hypothesis that P450 enzymes are involved in host-plant utilization by these Sonoran Desert Drosophila species.